Akizuki class Destroyer (1941)

IJN Type B class Destroyer: 39 planned, 12 built 1942-45: Akizuki, Teruzuki, Suzutsuki, Hatsuzuki, Niizuki, Wakatsuki, Shimotsuki, Fuyutsuki, Harutsuki, Yoizuki, Natsuzuki, Michitsuki, Hanazuki

The Akizuki class started with a 1939 directive, calling for specialized anti-aircraft escorts for carrier groups, the “B” types. In this new reorganization of Japanese destroyer forces, the “A” class were a replacement for the Yugumo (the prototype IJN Shimakaze), the “B” were AA escorts, and the “C” type the cheap ASW escort (later Matsu-Tachibana). The need of a dedicated escort went in parallel with the development of a brand-new gun mount, 100 mm (3.9 in) DP guns that were promising long range, high rate of fire and accuracy. Each ship carried no less than four of these, making them comparable to the British Tribals, but they ended much larger and similarly kept a single torpedo tubes bank. There were grand plans, with a total of 39 ships ordered in 1940, but only twelve were completed, including 4 of the sub-class Fuyutsuki, none of the next Michitsuki sub-class was completed and the last 23 B-Kai were never laid down.

Hatsuzuki on sea trials in 1942 (CC photo colourized by irootoko jr)

These destroyers were quite special. They reached 3,700 tons at full load, double that of a Fletcher-class, and sometimes dubbed by authors “super-destroyers”, a category popular from 1937, at the edge of earlier light cruisers (5,000 tons). They were not very fast at 33 knots unlike the Type A Shimakaze, targeting 39 knots, but this was enough for aircraft carrier or capital ship escort work. Not only their semi-automated turrets proved quite capable, almost on par with the US 5-in/38, but they were coupled with the Type 21, Type 13 and Type 21-22 radars for good measure. They also kept a limited torpedo and ASW capabilities, with a large hull enabling the installation of scores of 25 mm AA guns in single, twin and triple mounts.

In 1945, this jumped from twenty-nine to fifty-one barrels, making them the best-armed destroyers ever built. The Akitsuki had a strong hull and new protection measures for the machinery as well. They were tailored to survive the worst and showed it in combat.
Half of the Akitsuki entered service too late in 1945. Of the twelve operational, six were sunk in action (1 by submarine, 2 by aeroplanes, 3 by surface actions). IJN Akitsuki was launched in July 1941 but completed only after Pearl Harbor. Four others were launched in 1942, completed in 1943, one in 1943 and the last four in 1944, completed in 1945. Among the six survivors, one became Chinese (Fen Yang) and the others were ceded to USSR as war reparation.

Development

The Akizuki-class destroyers (Akizuki-class destroyers) were a class of 1st-class destroyers of the Imperial Japanese Navy, also called “Type B destroyers” after their original designations, and “Tsuki”-class destroyers after the names of individual ships according to their naming convention (see later). They were the first and last AA destroyers built by the Imperial Japanese Navy in the second world war, with twelve completed out of an original program much more ambitious.

No. 361 and later were also referred as the “Fuyutsuki-class and those with No. 365 and later were referred as the “Michitsuki-class” but according to the Imperial Japanese Navy’s official classification but at the end of the day, they were all Akizuki-class destroyers and on the recognition level, identical. For convenience, all are seen there together. Allied intel referred to both the Akizuki and Fuyuzuki-class as the “Teruzuki-class” destroyers, however, back in WW2. It’s modern authors, armed with surviving official Japanese documentation that re-named the class as we know today.
As for their deep origin, they went back to the post-WWI realization that air power was a new and serious threats for traditional fleets, and there were attempts by most naval powers in the interwar, to at least on paper, toy around with the idea of AA-dedicated ships, either light cruisers or destroyer. The principle was a combo of heavy anti-aircraft guns with high elevation and fire rate, combined with more traditional, lighter anti-aircraft guns as countermeasure against aircraft while in a group. They were intrinsically escort ships, protecting others assets in a flotilla.

In 1935, the Royal Navy for example started first a full conversion of two now obsolete C-class light cruisers, removing all main armament and torpedo tubes, for a combination of dual purpose and “pomp-pom” only. A year later in 1936, the Royal Navy started working on the Dido-class light cruisers, subsequently constructed, based on a new type of heavy AA gun.

The United States Navy saw this development and in 1937 started to plan an AA cruise class of its own, on the official purpose f replacing the vintage Omaha class light cruisers, resulting in the construction of the Atlanta-class from 1939. The Italians also studied such conversion prototypes, but none came out as concrete projects. The Japanese Navy of course lost nothing of it and proposed already in 1938 to convert its now outdated Tenryu-class light cruisers as specialized anti-aircraft cruisers, a plan that was even presented to Emperor Showa. Both would have seen their main guns replaced by standard 127mm dual-purpose mounts, Type 89.

The Imperial Japanese Navy’s AA plan was registered in 1939 (Showa 14) as part of the Naval Armaments Expansion Plan or “Plan IV”, which included also the construction of the Type A (Shimakaze) and six Type B, the Akizuki-class. The first was laid down in 1940 (Showa 15) and it was planned to mass-produce these, then deploy them as “fixed” escorts with capital ships, unlike traditional destroyers that can be detached for more offensive operations. Notably, these new destroyers would have the important task of protecting the newly built Yamato-class battleships, modified Yamato-class battleships and successors, as well as aircraft carriers.
The specifications were registered in 1938 (Showa 13) at the request of the Naval General Staff:
-Standard displacement: 2,200 tons
-Speed: 35 knots or more
-Range: 10,000 nautical miles at 18 knots
-Eight 10 cm anti-aircraft guns, four 25 mm machine guns, two depth charge launchers (30 depth charges) and two (40 depth charges).

Other equipment included smoke screen mortars to conceal the escorted vessels, and an aircraft rescue derrick. They were planned as a replacement for the previous carrier escort destroyers, which were considered too “torpedo heavy” for their task at hand. They could act now as plane guards, recovering precious pilots. Indeed, initially, no torpedo tubes were planned for the Type B. Their official classification was of pure “escort ships”. But as the design was refined and precise, calculations made, it was clear that the hull, created around two pairs of brand-new dual-purpose mounts, ended larger than expected, and for that size, the IJN started to think torpedoes would not be a waste.

Apart to the size and speed challenge, meeting the range requirements proved equally problematic. 10,000 nm would ensure, as escort, the possibility of keeping up with larger battleships and fleet carriers on very long deployments. This would have required a heavy fuel oil load, calculations showed it as much as 1,200 tons for a displacement of over 4,000 tons standard to reach the desired speed and range. Meaning, the “escorts” would likely be cruisers.

Therefore, the plan finalized in April 1939 reduced the speed to 33 knots and range to 8,000 nautical miles at 18 knots. This enabled to keep the hull much smaller, but the IJN staff still insisted upon having as a “guarantee”, like for any ship of that size and tonnage, torpedo tubes at least for self-defence. At this point, the armament now included a single quadruple torpedo tube with four in reserve, located between structures amidships. Given this addition, the naval staff was obliged to revise the classification from “escort” to “destroyer” for construction orders.
In all, six ships were planned under the AA Plan. An additional ten ships were planned for the 1941 Wartime Construction Plan (Marukyu Plan) and sixteen planned under the 1942 Armament Expansion Plan (Plan 5), but this was increased to 23 when the 1942 Wartime Ship Construction Supplement Plan (Revised Plan 5) was revised. The final total was 39 ships, 16 under Plan 5 and the final seven under the Revised Plan 5, called the “Revised Akizuki-class” destroyers with modifications to increase speed.

Names:

The class naming convention ended with the suffix “-zuki”, meaning “Moon”. Example: Yamazuki (山月) “Moon over a mountain”.
As usual, all matter of poetic declinations generated almost thirty names, extinguishing the possibilities, so new names were assigned for later ships:
N°5063 Aogumo (never ordered or laid down, cancelled in December 1944) was to inaugurate a brand new serie with the “-gumo” prefix for “cloud”. However earlier destroyers already “used” these names and choices were limited. Example Yukigumo (雪雲) Snow cloud.
So from hull N°5070 a new series was started with IJN Okitsukaze, the “-Kaze” (wind) being related to now obsolete 2nd class 1920s destroyers for 4 ships.
Then, there were two “-chi” (squall), and an exception, the last ship to be ordered, N°5076 Hae, (南風) a South wind of dialect word in Okinawa Prefecture, standard Japanese is Minamikaze
Hayaharu (早春) Early spring. The Imperial Japanese Navy sometimes referred to them collectively as the Tsuki-class (Moon class) after their names, even the sub-classes. There was a joke about this, saying, “They’re all named after teahouses.”

Design of the class

Unlike the Shimakaze, essentially a stretched-out Yugumo, the Akizuki were literally built around their new 100mm gun turrets. They were massive ships, albeit shorter than Shimakaze. Still, they looked more imposing than usual JN destroyers were larger (in beam notably) than standards, to be the point of sometimes be mistaken for a larger ship such as a Mogami-class cruiser or even a battleship.

Hull and general design

The class had a so-called forecastle-type hull which length was approximately one-third of the overall length, to accommodate two main guns, mounted forward. To minimize their center of gravity, the upper deck below the forecastle is sloped downwards, to keep the forward main guns as low as possible, making for an unusual faux low forecastle. Instead, also a double-curved bow, the bow of the Akizuki-class ships is nearly straight. The frame spacing was measured in 5mm increments in some locations. The outboard electrical wiring installed at completion.

Since they were also the first IJN AA ships they needed a new bridge. A full-scale model was constructed at the Maizuru Naval Arsenal in the spring of 1940 to be tested and thoroughly examined. This structure was three-tiered like for a Kagero-class, but its height was increased by 2 meters or a full deck to prevent the forward main guns from obstructing the view. The wheelhouse, previously located under the compass bridge, was now mounted over it to heave a clear view.
An open-air air defence command post was installed above the compass bridge, with bulwarks around the entire perimeter and windbreak forward. The captain could swap from navigation to AA defence and direct anti-aircraft fire from there. This came with a Type 94 anti-aircraft system on top supported by three columns, independent of the bridge structure. Two were exposed outside, behind the bridge.

When a radar was installed, the shelter deck below the signal station was expanded aft to create a radar room. The code room was expanded aft as well. The floor of the signal station deck was also expanded. The bulwark on the rear side of the compass bridge was lowered however to install the new Type 2 signal receiver.
On the Hatsuzuki, only the signal receiver position was lowered, and on subsequent ships the entire bulwark was lowered. However, from the “Fuyuzuki” onwards, the base of the bridge was expanded aft, creating an internal volume, and the radar room was located within the bridge, without any protrusion below the signal station. On the Haruzuki, the flagship facilities were located within the bridge, so the deckhouse protruded further from the expanded bridge and below the signal station.

Otherwise, the silhouette an Akizuki was very different from anything else that came before, dictated by these four twin turrets in two pairs of echeloned positions fore and aft. The great fear of engineers was this class to be top heavy, notably due to the superfiring forward turret (B) and the taller bridge. All possible measures were made to better manage weight distribution, as the Navy staff was adamant about this configuration. It was at some point to alleviate this by having “B” moved amidships and the forecastle shortened, or A and B being placed at the same level back to back. But the arc of fire was degraded in both cases, and it was unacceptable.

Akizuki, ONI drawing.

Powerplant

The boilers were the same as the Kagero-class, with three Ro-type Kanhon boilers, for the same steam pressure of 350 kg/cm² and steam temperature of 350°C. Two boilers were installed in the forward boiler room, one in the aft boiler room unlike for the Kagero-class, having one boiler per room. The wider hull enabled this. There were essentially the same Kanhon turbines as for the Kagero-class, for productivity reasons. The reduction gear was newly designed as well. The rotation speed was reduced however from 380 rpm to 340 rpm.

From the Hatsuharu-class onwards, destroyers up to the Kagero-class there were two turbines in the forward engine room, one on each side, plus an auxiliary machinery such as generators in the aft engine room. On the other hand, the Akizuki-class had the port turbine in the forward engine room and starboard turbine in the aft engine room. While the previous layout would be an issue forward machinery room was flooded by a hit, the ship could still operate even if only one machinery room was flooded. This improved survivability, though not as far as the shift engine system adopted by the later Matsu-class destroyers.

The starboard side of the forward machinery room and port side of the aft machinery room were equipped with heavy oil tanks (though the Kagero-class ships did not have heavy oil tanks on the port side of the machinery room). The Shimotsuki, which served in Ozawa’s Task Force during the Battle of Leyte Gulf, cites an example in which the heavy oil tank outside the port machinery room prevented flooding from a near miss, pointing out the risk of sudden flooding of the aft machinery room if a near miss hit the starboard side, where there was no heavy oil tank.

Furthermore, this was the first (and only) destroyer to employ a new type of funnel, a design adopted on Imperial Japanese Navy cruisers since the light cruiser Yubari, but unusual on destroyers. The lower part of the forward mast is four-legged, spanning the funnel, but then became three-legged at the height of the signal deck. To widen the field of fire for the AA control on top of the bridge, the spacing between the mast posts was narrowed and moved away from the bridge, as well ass slightly tilted backward. When the radar was installed, the design was changed yet again, creating a flat at the top of the mast, extending the mast behind the radar. At the same time, the lower part of the mast was reinforced.

Armament

The core of the design was the Type 98 10cm 65-caliber anti-aircraft gun. Initially it was though as a shortcut to use the old Type 89 12.7cm 40-caliber anti-aircraft gun, but it was slow in elevation, traverse and muzzle velocity. Some in the Navy were uncomfortable with the new calibre, smaller in calibre than its predecessor, but longer, so it was argued that the longer range and higher muzzle velocity were more than enough to compensate.

The main issue was found later, a short lifespan: the 12.7cm (5 inches) gun had a lifespan of approximately 1,000 rounds, whereas the 10cm gun only reached 350 rounds due to the higher pressure. To address this, the barrels were designed to be replaced using available shipboard equipment, and each ship would need thus to carry spare liners. However, due to this extra structural complexity, this was never put in place. It was suggested instead to carry entire spare barrels, but it was never done in practice. Replacing a 4t barrel at sea was indeed unrealistic at best with the on-board equipment.

The gun’s performance was high, however, with an unprecedented (for the calibre) maximum range of 19,500 meters, and maximum altitude of 14,700 meters plus 19 rounds per minute in the best conditions of continuous fire. However, the ammunition hoist malfunctioned after prolonged use, so the crew reverted to manual loading. Target acquisition using sights proved difficult in actual combat, and gunners were sometimes knocked unconscious by gases inside the turret, poorly ventilated.
The latter were twin A-type gun, two mounted on the forecastle, two on the aft deck in superfiring pairs like for US destroyer leaders or British Tribal class, French Mogador, Italian Capitani Romani. Both elevation and rotation were performed by a 20 kW electric motor.

They were aimed by the latest Type 94 AA system but it was way inferior to the US Mk. 37 Fire Control System. No firing radar and distance to AA targets as well as tracking were all manual, with optical systems. The guns were also manually traversed and elevated, so training was paramount. The original plan called for two Type 94 FCS, forward and aft but there were never enough. A single one was placed atop the bridge, directing all turrets. There was in fact a location and casing aft, but there was nothing inside, later replaced by a 25 mm mount. The 61st Destroyer Division (Hatsuzuki, Wakatsuki, Akizuki) at the Battle of the Philippine Sea showed this.

10cm/65 Type 98 naval gun

The 10 cm/65 Type 98 naval gun or “long 10cm high-angle gun”, was an intermediate dual purpose naval gun that saw service with the aircraft carrier Taihō, light cruiser Ōyodo, and the present destroyers.
The Japanese considered it their finest anti-aircraft artillery weapon and indeed, elevation was excellent for the task at 90°, and it could both traverse and elevate quickly, had a rate of fire well enough the unusual norm, yet still below the legendary U.S. 5-in/38 dual-purpose gun. It had poorer firing directors also in comparison and lacked radar proximity fuses. However, it was appreciated postwar both by the Chinese and Soviets that obtained destroyers as war reparation. Some were also used as land-based weapon, 32 protected the homeland, three were at Iwo Jima, two at Balikpapan, and they had quite a punch against US tanks. The model was first captured at Iwo Jima.

The 100 mm (3.9 in) L/65 calibre Type 98 gun was given a horizontal sliding breech that could be either monobloc or with an optional replaceable barrel liner construction, spring-powered rammer cocked by recoil enabling loading at any elevation and be kept at the target at all times. In all 116 were manufactured, but it soon appeared the barrel service life was poor, at 350-400 full charges, given its high muzzle velocity.
The twin gun turrets associated weighted 34,500 kg (76,100 lb) and on the Akizuki class, they could traverse at 12° to 16° per second, elevate at 16° per second, electro-hydraulically powered with manual backup. The shells were either 100 mm (3.9 in), 28 kg (62 lb), fixed, HE with brass casing, nose-fused (contact).

⚙ specs. 100mm/65 Type 98 100 millimetres (3.9 in)
Weight	Mount: 34.5t (76,100 lb)
Barrel/td>	3t barrel & breech, 6.73 metres (22.1 ft) bore (65 cal)
Elevation/Traverse	-10° to +90°, 200°
Loading system	See notes, powered ramming
Muzzle velocity	1,010 m/s (3,314 ft/s)
Range	19,500 metres (21,300 yd), 13,000 metres (43,000 ft) 90°*
Crew	6-8
Round	HE fused 100 x 819mm .R 13 kilograms (29 lb)
Rate of Fire	20-22 RPM

*Effective Horizontal range: 14,000 metres (15,000 yd), Vertical effective ceiling: 11,000 metres (36,000 ft)

Torpedoes: Single quad Tube

As mentioned above, initial plan were not to carry torpedoes at all, but it revised to include them mid-way through construction. The was half that of the Kagero-class fleet-class destroyers, with one Type 92 quadruple torpedo tube with a reloading mechanism, same as a Kagero-class, and eight “long lance” four in tubes four in spares. From Fuyutsuki onwards, the plan became not to carry spare torpedoes, with only four in the tubes. However in February 1944, spare torpedoes were reinstated and a spare torpedo storage case similar to that of Akizuki was installed for a return to eight torpedoes.

Type 93 (1933)

The Type 93 entered service in 1933 (model 1) and the ships were possibly rearmed in 1935-36 or never, it’s not strictly confirmed. The Type 90 could have been installed instead when available.
61 cm Type 93 torpedo found on the Mutsuki, Fubuki, Akatsuki classes, and all oxygen fuelled from the Hatsuhara and beyond. The Designer was Rear Admiral Kaneji Kishimoto, and Captain Toshihide Asakuma, and this started in 1928 (just as the last Mutsuki class ships were completed), then went on until 1932. The Type 93 became the notorious “secret weapon” unleashed by IJN destroyers and cruisers in WW2, which caused extensive damage during the Solomons campaign especially. The defective US Type 14 torpedo was in stark contrast with this. The Type 93 torpedo was dangerous to its user however but its effectiveness outweighed the risks anyway, claiming 23 Allied warships, 11 cruisers, 11 destroyers, and a fleet aircraft carrier and among these, 13 hits were fatal.

⚙ specifications Type 93
Weight	2.7 tonnes (6000 lb)
Dimensions	9 metres (29 ft 6+5⁄16 in) x 610 mm (2 ft 1⁄64 in)
Propulsion	Oxygen-enriched air
Range/speed setting	2,000 m (24,000 yd) at 48–50 kts or 40,400 m (44,200 yd) at 34–36 kts
Max speed	96 km/h (52 kn)
Warhead	490 kg (1080 lb)
Guidance	Straight course

25 mm Type 96

Two twin mounts originally were placed sideways of the funnel’s truncating, ahead of the torpedo tubes, but there was no fire control system, as the guns were directly aimed and operated manually. In early 1943, gun mounts were added to the left and right sides of the funnel on the boiler intakes this time, triple mounts, while the twin guns were replaced by triple ones. It is believed their gun mounts were expanded to accommodate triple guns as well in the design.

Later a gun mount was installed on the support tube at the rear anti-aircraft system, with a triple gun added.
The Fuyutsuki subclasses were fitted with two twin gun mounts on both sides for two triple guns. The Akizuki and other ships lacked gun mounts on both sides of the funnel. Instead, four triple mounts, notably for the central gun mount, were planned. When Fuyuzuki was completed by May 1944 she had a triple mount on the rear anti-aircraft mount, similar to Akizuki and other ships, for a total of five triple.

By the time of Operation A-Go in June 1944, the Akizuki-class had indeed five triple mounts. Although this varied by ship, single guns were added after Operation A. By February 1945, all except Haruzuki had gun mounts on the left and right sides of the bridge, each triple for seven triple. The Harutsuki had flagship facilities inside the bridge that prevented that.

The type 96 25 mm AT/AA gun became the standard of the IJA and IJN, an automatic cannon developed as a variant of the French Hotchkiss 25 mm, dual-purpose and developed as AA on single, twin and triple mounts. Development worked on 1935. 25 mm Hotchkiss design evaluated and order placed for several mounts types for evaluation at Yokosuka Naval Arsenal. It led to the Type 94 and Type 95 and then the main model produced at Yokosuka Arsenal, the Type 96. Elements made with castings and not forging for larger production, Rheinmetall suppressor, new mounts designed.
Air-cooled gas operated with multiple rings (Hotchkiss patent). Twin-mount in 1939, followed by triple mount in 1941 and single mount in 1943.
Issues of the designed revealed in combat:
Slow elevation and traverse, ineffective sights, excessive vibration, limited magazine cap., blinding Flashes. The 1944 single mount needed a single operator and a loader, but had a better spiderweb sight.

Tech specifications 25 mm Type 96
Barrel Lenght	1.5 m (4 ft 11 in) L/60
Barrel weights: Single	785 kg (1,731 lb)
Barrel weights: Twin	1,100 kg (2,400 lb)
Barrel weights: Triple	1,800 kg (4,000 lb)
Crew:	3, 7 and 9 respectively
Shell	25×163mm
Exact caliber	25 mm (0.98 in)
Action	Gas operated
Elevation/Traverse	-10°/+85° – 360°, manual
Rate of fire	200–260 rpm (cyclic)
Muzzle velocity	820 m/s (2,700 ft/s)
Effective range	6.8 km (4.2 mi) at 45° with HE shell
Maximum firing range 85°	3 km (9,800 ft) effective, 5.5 km (18,000 ft) max.
Feed system	15-round box magazine
Production	33,000 all variants 1935-45

13.2 mm Type 93 heavy machine gun

The Type 93 13 mm (0.55 inches) heavy machine gun (九三式十三粍機銃), Type Ho 13 mm AA machine cannon was a license-built version of the French Hotchkiss M1930 machine gun. It was widely used for heavy ground support and organic for AA defence, until gradually replaced when possible by the 25 mm Type 96. They were still in use, on twin mounts, on many IJN cruisers and destroyers before WW2 but gradually replaced when possible, notably by single 25 mm mounts due to unsufficient range and firepower.

The common twin mount in 1941

Tech specifications Type 93 heavy machine gun
Barrel Lenght	140 centimeters (55 in) total, 988 millimeters (38.9 in) barrel alone
Mass	42 kilograms (93 lb) (empty)
Fully loaded	?
Shell	13.2×99mm Hotchkiss
Exact caliber	13.2 mm
Barrel type	A tube with progressive RH parabolic twist, 9 grooves
Action	Gas-operated fully automatic
Elevation/Traverse	-15 / +85°, 360° traverse, manual
Rate of fire	450 rounds/min Max
Muzzle velocity	?
Effective range	1,000 meters (3,300 ft)
Maximum firing range 45°	?
Feed system	Classic box magazine holding 30 rounds
Sight	Spiderweb anti-aircraft iron sight

Depth Charges

The ship was equipped with two Type 94 depth charge projectors, six depth charge launchers, and 54 Type 95 depth charges. The Asashio-class to Yuugumo-class fleet destroyers were equipped with one depth charge launcher and 18 or 36 depth charges (when not equipped with deep mine sweeping equipment), while the Akizuki-class, tasked with direct escort of aircraft carriers, had more powerful anti-submarine armament.
From Shimotsuki onwards, completed in March 1944, the depth charge platform was replaced with two depth charge tracks. It is likely that earlier ships were also converted to tracks at the same time. The tracks were the equivalent of six depth charges, with the starboard one being longer, likely extended forward for transport purposes. (The Wakatsuki and Shimotsuki had their port side extended.)
The single Type 81 depth charge launcher at the stern could allow dropping the standard Type 95, 30.5″ by 17.7″ (77.5cm by 45cm). 220 lb (100 kg) charge, Type 88 explosive (ammonium perchlorate and ferrosilicate). Fuse using a water inlet. 100 feet (30m) and 200 feet (60m) settings (after the revelations of a US Congressman).
Later increased to 324 lb (147kg), Type 97 explosive (70% TNA/30% HNDA), 300 foot (90m) setting.
-1944 Type 2: 230 lbs (105kg) Type 97 explosive settings 98, 197, 292, 390, 480 feet (30m, 60m, 89m, 120m, and 145m).
-1945 Type 2: 357 lbs (162kg) explosives.

Sensors

The installation of radar was not planned initially, and the Akizuki class ships were not equipped when completed. However, it will change fast, and from Hatsuzuki onwards, completed on December 29, 1942, the next Fuyuzuki class ships were given at completion a Type 21 radar while the foremast was modified accordingly. This may have been the case for Suzuzuki, completed on the same day as Hatsuzuki. From an order of August 26, 1943, an additional Type 21 radar was to be mounted on foremasts of all ships by early November 1943.

In early July 1944, Akizuki was fitted with an additional Type 13 radar on the aft mast. It remained unconfirmed for other Akizuki-class ships, if equipped with similar radars for “Operation A”.
Some ships had the Type 21 removed from the forward mast at the time of the Battle of Leyte Gulf in October 1944 with a second Type 13 radar, a Type 22 in its place. The Type 13 radars covered the forward and aft angles. The timing of these additions is unclear, for Suzutsuki and Fuyutsuki, but photographs confirm this addition was made. A battle report for Shimotsuki indicates clearly she had both radars. From Harutsuki onwards, this configuration was adopted while in construction.

As was the case with others, the Akizuki-class lacked a proper targeting system to link up the main guns and AA guns to the radar. This limited effectiveness when firing. Nevertheless, the radar was an essential item for AA combat still, allowing to prepare the crews with information such as the number, formation, direction, and distance of incoming aircraft.

Type 21 radar

The Type 21 was a large anti-aircraft radar and was equipped on large ships such as battleships, aircraft carriers, and cruisers, but was only equipped on destroyers of the Akizuki class.

Type 22 radar

The Type 22 radar was available from November 1943, and by late 1944, it started to be replaced in turn by the Type 13 radar, or in some case was alternative to the Type 21. The early Type 22 General Purpose Radar looks like characteristically like a 2910 lb (1320 kg) drum topped with a twin cornet amplificators, mounted mid-way top the mast.

Type 22 radar Specs:

The Type 22 radar was a small and lightweight surface radar, and was also fitted to other destroyers.
Wavelength 10 cm, pwd 10 microsecond, PRF 2500 Hz, scan rate 5 rpm, PP 2 kW
Range: 20 nautical miles (35 km) aircraft group, 10 nm (17 km) single, 13 nm(24 km) battleship.
Subject to land clutter. Horn and A scope display, accuracy 220 yards (200m)/3 degrees res. 1600 yards (1500 m)/40 degrees
300 sets produced installed on destroyers from the summer 1942. Generalized in 1944.

Type 13 radar

The Type 13 was a small and lightweight anti-aircraft radar, and was therefore also fitted to other destroyers.
Vertical 240 lb(110 kg) bedframe antenna, developed 1941, introduced mi-1943, with vertical dipole transmitter and Yagi mattress receiver. 1000 sets produced. Air defense, range 100 km (group), and single aircraft 50km.
Specs:
Wavelength 200 cm, pw 10 ms, PRF 500 Hz PP 10 kW
Range: 30-60 nautical miles (50-100 km)

Evolution: Sub-classes

Fuyutsuki class

Project number F51. This subclass were originally following the same specifications, but construction was simplified due to wartime emergency and lack of labour time and resources. Only four vessels were built under this new Maru Kyū Programme (Ship # 361–364). This was still cosmetic. They had a simplified bow design, rear deck house modified, and they received two-dimensional air inlet for boilers, much simplified.
Also: the bow of the original Akizuki curved gently below the bottom, but from Fuyutsuki onwards, it was straight down to the bottom, albeit Yoizuki shown on photos a bow partially cut off at an angle below the waterline, and it’s unclear whether this was a feature unique to her or other ships were similar. The bowl-shaped intakes for boilers No. 2 and No. 3 were discontinued as well. Intakes were relocated on the side of the funnel and under the axial 25mm gun mounts. The front half of the aft deckhouse was removed, the aft wheelhouse was installed above the intake and exhaust port doubling as searchlight tower, making it a separate superstructure from the aft deckhouse. The aft mast’s legs were also wider and angled differently due to the installation of the Type 13 radar to offer a better support. The pillars also appeared to have no longer round but square beams and angle beams also for simplification.

The 25 mm Type 96 mounts and searchlight towers also became polygonal. The 25 mm, originally planned to be twelve in four triple mounts (Akizuki: two twin mounts) saw the central Type 96 AA was installed behind the funnel, instead of on both sides of the aft steering house, behind the launch tubes. The removal of spare torpedoes was mandatory to compensate for the addition of AA guns but were returned around February 1944, with identical spare torpedo storage cases as the Akizuki. The starboard torpedo davit however was removed, the torpedo transport track was changed to one with a branching point along the way. Depth charges went to 72 (54 on Akizuki) and a Type 21 radar was included from the start. The boats went from 8 m motorboats to 8m cutters, also for simplification. The air intake for No. 1 boiler and sides of the aft deckhouse were changed also from curved to flat.
After entering service from May 1944 to April 1945, Fuyutuki, Harutsuki, Yoiozuki and Natsuzuki however displeased the IJN and further modifications were ordered, leading to the next Michitsuki sub-class.

Michitsuki class

These follow-ups were designated Project number F53. This was the final effective, not paper production model of this class. They were simplified and rationalized further compared to the Fuyutsuki class and in total concerned five ships in the Maru Kyū Programme (Ship # 365–369) but also sixteen more in the Additional Naval Armaments Supplement Programme (Ship #770-785). As the 1941 Additional Naval Armaments Supplement Programme was replaced by the Maru 5 Programme, so these ships took hull numbers #5061-5076, and six more were added, #5077-5082. Of all these, only one was completed. Some authors risk the unofficial “akizuki-kai” but these were only simplified for easier production at a time the Japanese industry was desperate, bombed and starved from men and resources alike. The proper “Akizuki-class Kai” sometimes mentioned referred also sometimes as the Akizuki-class Kai, Akizuki Kai, or even “Super Akizuki”. They were indeed planned ships under provisional names: No. 770 to No. 785, final seven ships of the Planned Kai had provisional names: No. 5077 to No. 5083. They were essentially upgraded to the same engine output as the Shimakaze with a planned speed of 36.7 knots and likely a bit longer than the standard.

Of the two ordered, one at Sasebo (Michitsuki), and Maizuru (Hanazuki) only the latter was completed in December 1944 and saw some service, even surviving the war. But these simplifications paid off in terms of speeding up construction. As an example, the last of the class, IJN Hanazuki, was laid down at Maizuru on 10 February 1944, launched on 10 October 1944 and commissioned on 26 December 1944, so just 11 months. To compare, IJN Akizuki, was laid down in June 1940 and completed in June 1942, so two years full. This feat, usual for US naval Yards, but not for Japanese Yards, was performed by Maizuru Naval Arsenal, the same that built the first ship and “wrote the book” on these simplifications. IJN Fuyutsuki, the first simplified subclass was also built at Maizuru and already built in the span of just a year, from May 1943 to May 1944.

The Other Yards ordered these ships were the following:
Maizuru Naval Arsenal: Akizuki, Hatsuzuki, Fuyutsuki, Kiyotsuki, Hazuki, Hanazuki
Mitsubishi-Nagasaki Shipyard: Teruzuki, Suzutsuki, Niizuki, Wakatsuki, Shimotsuki
Sasebo Naval Arsenal: Harutsuki, Natsuzuki, Michitsuki (incomplete)
Uraga Dock Company: Yoizuki.

The next ships to be ordered were the following:
367 Kiyotsuki (Maizuru Naval Arsenal)
368 Ōtsuki (Sasebo Naval Arsenal)
369 Hazuki (Maizuru Naval Arsenal)
5061 Yamazuki (none)
5062 Urazuki (none)
5063 Aogumo (none)
5064 Benigumo (none)
5065 Harugumo (none)
All Cancelled on 14 December 1944.

5066 Amagumo
5067 Yaegumo
5068 Fuyugumo
5069 Yukigumo
5070 Okitsukaze
5071 Shimokaze
5072 Asagochi
5073 Ōkaze
5074 Kochi
5075 Nishikaze
5076 Hae
All Cancelled on 9 June 1944.

Mangetsu class

The Mangetsu-class, Seigetsu-class or modified Fuyutsuki-class, modified Akizuki-class started with ship No. 367 (planned name “Seigetsu”) up to ship No. 5076 (planned ship “Minamikaze”) as a revision of the Maru 19 Line approved on May 5, 1944, calling for significant simplification in construction for the next ships. The hull use more straight lines, special steel was abandoned for regular steel, so this traduced in a slight increase in displacement and decrease in speed. The construction tome from laying down to completion was expected to be reduced to an average of 8-9 months. Externally, the curves were significantly reduced, the stern shape was revised, without slopes. Type 4 hydrophones were mounted as standard, creating also a bulged underneath. The bridge and bow of Suzutsuki, after repairs, are a good example of what it would look like.

There are various theories as to whether Mangetsu No. 365 and Kagetsu No. 366 should be considered Fuyutsuki-class or the Mangetsu-class.
In “Photographs of Japanese Warships, Volume 11,” both are classified as the Mangetsu-class.
In “Anti-Aircraft Guns and Air Defense Ships,” the Mangetsu are classified as the Mangetsu-class and the Kagetsu as the Fuyutsuki-class.
In “Pacific War History Series, Vol. 23: Akizuki-class Destroyers,” the Kagetsu is included in the Fuyutsuki-class because photographs do not show the extensive simplified construction seen on the Mangets. The surviving drawings show that the above-mentioned significant simplifications would be implemented starting with the “Ship No. 367” (Seigetsu), and if this were applied, this type would become the Seigetsu-class.

General Evaluation

The fearsome Type A (Shimakaze)
The Akizuki were arguable the best IJN destroyer of the war. Not because the Type A Shimakaze was better, in pure terms of traditional destroyer design, replacing the previous Kagero-Yugumo, the Shimakaze was really the apex of IJN destroyer design, outclassing everything comparable worldwide in speed and torpedo armament. But on an industrial perspective, it was just way too complex and costly for mass production. If Japan had succeeded to maintain its “co-prosperity” empire free from US submarines and aviation predation, with resources flowing without interruption, perhaps it would have been viable to field a division of these (six ships).

But they were just a bit too ambitious in a 1943 scenario as it unravelled.
In contrast, the Akizuki had a less ambitious, more limited goal of AA escorts, and they excelled in that. The Type B were also less expensive (still far more than a Type C/D escort !), the speed, protection and range were at least “good enough” for their task, and even better than average destroyers, but moreover, the combination of a large hull accomodating an unprecedented light AA combined with their baseline, really excellent 100 mm dual-purpose guns, made them infintiley more valuable in 1944 as the events went, than the Shimakaze, which were nothing more than a continuation of prewar Japanese night attack doctrines placing an emphasis on speed and torpedo warfare.

But by 1944, especially after June, only AA defence mattered, and this class proved the very best asset the IJN ever had, even if it was too few, too late to counter the staggering amount of USN air power alone. These ships were good, but still overwhelmed. And to compare, a Gearing class in 1945 with its six 5-in/38 (two fewer barrels) and two quad TT banks was still superior in many ways. Not only its artillery was radar-directed with more speed than more traditional way of directing AA fire on the Akizuki, but they were of higher caliber (127mm vs. 100 mm) and more so, the HE shells used proximity fuses, a “secret weapon” probably even more valuable than the Japanese own “long lances” at this stage. And to close it off, despite having 40-50 of their 25 mm guns, this was still way inferior to the combination of twelve 40 mm Bofors and eleven 20 mm Oerlikon, due to better targeting again, and just better performances overall. Heck, the shortages meant the Akizuki still had to do with 13.2 mm heavy machine guns, it’s like if the USN still deployed M2 Browning 0.5 cal. at this stage…
The Akizuki class Postwar: Unlike most WW2 IJN destroyers, the Akizuki, with their large size, heavy AA armament and very efficient main dual purpose guns, the very best and finest ever fielded by the Japanese Empire, were very valuable after the war. In the winter of 1945, there were six still “operational” in various states of maintenance. They were soon chosen for transfer as war reparation.

Old author’s profile of Fuyizuki

⚙ Akizuki specifications
Displacement	2,700 long tons standard, 3,200-3,500t FL
Dimensions	134.2 x 11.6 x 4.15 (440 ft 3 in x 38 ft 1 in x 13 ft 7 in)
Propulsion	2 shafts GST, 3× WT boilers 52,000 shp (38,776 kW)
Speed	33 knots (61 km/h; 38 mph)
Range	8,000 nmi (15,000 km; 9,200 mi) at 18 knots (33 km/h; 21 mph)
Armament (1942)	4×2 100 mm DP, 2×2 25 mm Type 96, 1×4 610 mm (24 in) TTs, 56 DCs
Armament (1945)	Same but 7×3, 26× 25 mm Type 96 AA guns, 3× 13 mm AA guns
Sensors	Type 13, 21, 22 radars, see notes
Crew	263(1942), 315 (1945)

Career of the Akitsuki class destroyer

The Akizuki class in operations

As for operations, …the Akizuki class were the only destroyers for which every ship in class was commissioned during WW2, and immediately thrown into action. Akizuki escorted aircraft carriers at the battle of the Eastern Solomons on 24 August 1942, was at the Empress Augusta Bay, and survived the raid in October during trying to escort Yura. Teruzuki escorted aircraft carriers at the battle of Santa Cruz, naval battle of Guadalcanal on 13–15 November, co-claiming USS Cushing with gunfire, and even trying to sink USS South Dakota, then assisted sinking Kirishima in the second battle. She was one of rare case of IJN destroyer siunk by PT Boats (PT-37 and PT-40), proving the validity of the type.
From 1943 Akizuki crippled USS Nautilus, and took part in the Solomon Islands campaign. Niizuki was at the battle of Kula Gulf, claiming USS Strong at nearly 22,000 yards onoy to be sunk by cruiser gunfire.

In November, Wakatsuki was at the battle of the Empress Augusta Bay, and survived the raid of Rabaul. From 1944, Suzutsuki amazingly survived two torpedoes from USS Sturgeon (bow and stern lost), towed to repairs, only to be sent back by USS Besugo. Akizuki, Hatsuzuki, Wakatsuki, and Shimotsuki escorted aircraft carriers at the battle of Cape Engano (Leyte Gulf) seeing the end of Akizuki and Hatsuzuki. Fuyutsuki was later sent packing by USS Trepang, and in November, Wakatsuki sunk by aviation at the battle of Ormoc Bay.
In 1945, Shimotsuki was sent to the bottom by USS Cavalla. More ships in class were commissioned but stayed in port, lacking fuel oil and ammunition. Suzutsuki and Fuyutsuki escorted Yamato during Operation Ten Go: Suzutsuki lost her bow …a third time, Fuyutsuki was badly damaged by rocket fire and the the six surviving ships remained stuck in port until V-Day. Postwar, Suzutsuki and Fuyutsuki were scuttled as breakwater ships, Natsuzuki scrapped, Hanazuki sunk as target, while Yoizuki and Harutsuki were attributed to the Chinese and Soviet navy respectively, having a long career.

Akizuki (1941)

Akizuki (104, 秋月) was laid down at Maizuru Naval Arsenal on 30 June 1940, launched on 2 July 1941 and commissioned on 11 June 1942. She took part not long after to the Battle of the Eastern Solomons on 24 August, remaining unscathed. In the Guadalcanal Campaign she guarded transports but took a bomb hit and near misses on October (11 killed, 22 injured) down to 23 knots. She hhad to be repairs in Japan from 8 November to 16 December 1942. On 19 January 1943, she was torpedoed by USS Nautilus, having a boiler room flooded starboard (14 killed, 64 injured) down to 20 knots, with emergency steering. She had repairs at Truk on February 2-11 March alongside IJN Akashi just to return to Japan, but it was soon observed her bow started sagging. Her captain beached her at Saipan.

Later she was cut in half, bridge and forward turrets removed to lighten her up, while a temporary “wave-cutter” bow and temporary bridge ere constructed behind the mainmast so to return to Japan. There she was repaired from July to October, receiving the bow from the incomplete Shimotsuki. Newt she took part in the Battle of the Philippine Sea, rescuing survivors from Taiho and protecting Zuikaku from air attack, her main role.
By October 1944 she was in the Northern Force (Vice Admiral Jisaburo Ozawa) during the invasion of Leyte counter operation. On 25 October she met her fate at the Battle off Cape Engaño, east-northeast of of the Cape during the U.S. air attack by one aircraft from Task Force 38. Full Logs

Teruzuki (1941)

Teruzuki (105, 照月) was laid down at Mitsubishi-Nagasaki Shipyard on 13 November 1940, launched on 21 November 1941 and commissioned on 31 August 1942. She spent the next month training, assigned to DesDiv 10, 3rd Fleet from 7 October. In Truk with her squadron she escorted the three aircraft carriers of the Third Fleet in the Guadalcanal Island campaign.
At the Battle of the Santa Cruz Islands on 26–27 October, Teruzuki was near-missed by a Douglas SBD Dauntless the first day. That night she was targeted by a PBY Catalina of the “black cats”, near-missed by a 500-pound (230 kg) bomb which damaged hull, superstructures and killed seven crewmen. She was repaired in Truk. She departed with her unit on 9 November to meet Vice Admiral Hiroaki Abe en route to shell Henderson Field on 12-13 November. Yamamoto wanted this to lure out remaining US carriers into a night battle in the waters off Guadalcanal.
The force was marred by badl weather, heavy rainstorm and they were spotted by US radar at 27,100 yards (24,800 m), by Admiral Daniel Callaghan’s cruisers. When the battle commenced the Japanese were scattered in small groups. Teruzuki was trailing the northern column, too far away to assist and Hiei and Kirishima blocked her view. Next she engaged USS Atlanta and destroyers Cushing and Sterett, but lost track and 30 min. later, she spotted Sterett, crippled her by gunfire and then sank the destroyers Laffey and Monssen, with probably one of her torpedoes blewing Laffey’s stern. Next morning Teruzuki escorted Hiei to safety. Despite her efforts, Avenger torpedo bombers finished her off.

On 14 November, she wa spart of the Emergency Bombardment Force (VADM Kondō Nobutak) which approached Guadalcanal, forces split into three sections, herself in a sweep east of Savo Island under RADM Kimura Susumu and Hashimoto Shintarō. Hashimoto’s ships in the lead spotted initially “four destroyers and two cruisers” north of Savo at 23:10 and a sweep west of Savo was attempted in a pincer. Rear Admiral Willis in reality had two battleships: USS Washington and South Dakota, four destroyers, sent to stop any bombardment of Henderson Field. Washington’s radar picked them at midnight and the battle commenced at 00:17. There was a short exchanged and eventually Kimura’s ships withdrew to reload torpedoes, Kondō sailing to Lunga Point. Later Kirishima and Washington dueled but the rest of the Bombardment Force including Teruzuki, fired on South Dakota. No torpedo hit but her superstructure was wrecked and she lost radars and FCS. Later Washington turned south to avoid torpedo attacks, Kondō ordered Teruzuki and Asagumo to pursue her, but they could not catch up. The a general withdrawal came. Terukuzi tried to find Kirishima, discovered at 02:43, and she was later sunk at 03:23. Teruzuki and Asagumo, Samidare, rescued 1,128 sailors.
After repairs at Truk on 18 November and flagship of her unit, she struck a reef on 3 December. Next she was in the Shortland Islands on 7 December, as flagship of RADM Raizō Tanaka DesDiv 2. Her role was to deliver supplies to Guadalcanal (water-tight drums using currents). On 11 December five destroyers escorted by five others including Teruzuki. Theu sruvived an attack by 14 Dauntless. Teruzuki covered their withdrawal at 12 knots near Savo Island when surprised and attacked by three PT boats. She was hit by two 18-in torpedoes in the stern, lost rudder and propeller shaft, rupturing an oil tank causing a fire. Tanaka was transferred to another destroyer at 01:33. The fire reached a DC magazine detonating at 04:40, sinking her. 9 men were killed, Naganami and Arashi rescued 197 and 156 men swam to Guadalcanal. She was stricken on 15 January 1943, her wreck was rediscovered on 10 July 2025 by Robert Ballard.

Suzutsuki (1942)

Suzutsuki (106, 涼月) was laid down at Mitsubishi-Nagasaki Shipyard on 15 March 1941, launched on 3 March 1942 and commissioned on 29 December 1942. On September 10, Lt. Col. Tsuguto Akazawa, commander of Shiranui (Kagerō class) was appointed Chief of Equipment on Suzutsuki in completion. On September 13, Suzutsuki started outfitting and is completed on December 29 with Akazawa appointed captain. She is registered at Sasebo naval base with Hatsuzuki, and Yūgumo-class Ōnami, starting as patrol destroyer. Next she is sent to Yokosuka naval base and with Hatsuzuki she is assigned to the 3rd Fleet (Ozawa) on 15 January, 10th Squadron, DesDiv 61 (led by Akizuki with Teruzuki, and later replacing the latter when torpedoed by December 1942. The division was made of Akizuki, Suzutsuki, Hatsuzuki afterwards.
On January 15, Suzutsuki left Yokosuka for Kure and hunted down USS Haddock off Shionomisaki. On the 19th she started operations in the Solomon, with USS Nautilus taking Akizuki so Suzutsuki and Hatsuzuki returned to escort the Japanese fleet from Truk to Sasebo (Kongō, Haruna, Nisshin, Tone, Shigure). For Operation I-Go, to New Guinea on March 22, Suzutsuki joins three destroyers, to escort Jun’yō and Hiyō, Tone and Chikuma at Truk on March 27–28. The operation started by a voyage to Rabaul from April 2, but a day later Aoba is severely damaged in Kavieng. They arrived on April 4, Suzutsuki departs back to Truk and until mid-may, made this trip several times. On July 18 they escort 8th Sentai (Tone and Chikuma), 10th Sentai (Agano, Mogami, Oyodo), and DesDiv 4 (Arashi, Hagikaze) from Truk with the DesDiv 17 (Isokaze) to Rabaul, with two transport supplies to Buin and Buka Islands. Thye were back to Truk on the 26th.
Next, the 61st Destroyer Division (Suzutsuki, Hatsutsuki) multiplied such missioned to Truk, Rabaul, and Kwajalein until early September. On August 15 the are reinforced by Wakatsuki. In September-October, they headed for the Marshalls. On October 31, Akizuki returns after a refit, with the division now full (four Akizuki-class: Suzutsuki, Hatsutsuki, Wakatsuki, and Akizuki).
On November 10, Suzutsuki was escorting a convoy to Truk from Rabaul, when ship Tokyo Maru was heavily damaged by a storm. Suzutsuki assisted her, when hearing Agano was torpedoed by USS Scamp (SS-277) and went to help and escorted her back to Truk.
In early 1944, Suzutsuki escorted transports to Wake Island when torpedoed by USS Sturgeon (SS-187) (130 men KiA, inc. Colonel Tomari): One torpedo hit her forward magazine, severing her bow past the No.2 3.9 in dual purpose turret and the second severed the stern past the No.4 dual-purpose turret. She however had her bulkhead holding, and the central section could be towed by Hatsuzuki to Sukumo Bay.Eventually she was towed back to Kure Naval Arsenal on January 19. Repairs went on until August 3. A newly designed straight bow and angular bridge were built, a new stern section, and she returned to DesDiv 61 after shakedown in the Seto Inland Sea.
On October 16, Suzutsuki escorted a convoy from Keelung (Taiwan) when torpedoed by USS Besugo (SS-321) and sent back to Kure for repairs untl November. On the 23th she escorted Junyo in an emergency transport mission to Manila, then Haruna back to Japan in December, ambushed underway by a wolfpack (USS Redfish, USS Seadevil, USS Plaice) on December 9 in front of Sasebo. Suzutsuki was damaged by a typhoon and needed repairs in Kure until December 27, the shakedown in Seto Inland Sea. She was modernized and refitted but the lack of fuel restricted operations.
There was an air raid on Kure on March 19, as she escorted Yamato in Hiroshima Bay, no damage.
Her last mission was Operation Ten-Go:
At 3:00 p.m. on April 6 she was part of the “Special Attack Force” (1st Strike Force) under VADM Seiichi Ito, 2nd Fleet, 1st Air Squadron onboard Yamato, 2nd Torpedo Squadron, light cruiser Yahagi, DesDiv 17 (Isokaze, Yukikaze, Hamakaze), 21 (Asashimo, Kasumi, Hatsushimo), 41 (Fuyutsuki, Suzutsuki) from Tokuyama. Suzutsuki took position on the right flank of Yamato and from April 7, to her port rear. Asashimo had dropped out due to engine failure and was later attacked and sunk by aircraft.
At 12:32, the first wave from TF 58 arrived. Suzutsuki continued to cover Yamato’s port rear. Yahagi was nadly hit and Hamakaze sank and around 13:08, Suzutsuki received a 150 kg bomb from a SB2C Helldiver from USS Essex (CV-9), in front of her bridge, holing her forecastle deck, upper deck, and explosind on her starboard side. Turrets #1 and #2 were lost but the ammunition magazines in #1 was flooded. Power was lost, turret #2 exploded after a fire. The engine department personnel managed to keep 20 knots, but she lost her steering and condemnd to turn to starboard when Yamato turned to port (also rudder failure), missing each others by 50m. At around 1:30 p.m., a second wave arrived on the Yamato Guard Group (Fuyutsuki, Hatsushimo, Yukikaze, Kasumi), Yahagi was away, badly damaged assisted by Isokaze. Suzutsuki was apparently misidentified as a light cruiser by pilots and Yahagi was laterr sank, Kasumi badly damaged as well as Isokaze, which sailed north on her own.
Captain Hirayama on Suzutsuki, decided by himself the operation lost surprise and there was no point going on, so he proceded returning to to base at around 14:30 after Yamato sank. He did that by reversing at 20 knots. A lone TBF Avenger from USS Intrepid (CV-11) launched a torpedo but missed her. Suzutsuki was later escorted by Hatsushimo and crossed later Isokaze, offshore for emergency repairs. She later ended in the reserve Fleet as the three months of repair started, secheduled on May 5. Her hole was plated over with beams but her first and second turrets and AA were removed. She departed Sasebo on 10 June for Ainoura with her rear turrets. On 5 July, she was rremoved from her division and entered the 4th reserve with a crew of 100 people, on her own, isolated. Her crew even organized a farming team and a fishing team, cultivating pumpkins and potatoes, using local fishing boats. In July and August she saw AA action several times, claiming a P-51 Mustang in August. On November 20, she was stricken.
Postwar, she was used as a demobilization transport, transferred to Sasebo and started from April 1 to May 31, 1948 she was BU, starting with her superstructure. Her hull was used as a breakwater at Wakamatsu Port, completely buried. Today a part is still visible near Wakamatsu Canal, Hibikinada Rinkai Industrial Park.

IJN Hatsuzuki (1942)

Hatsuzuki (107, 初月) was laid down at Maizuru Naval Arsenal on 25 July 1941, launched on 3 April 1942 and commissioned on 29 December 1942. In October 1944 Hatsuzuki entered the Northern Force commanded by Ozawa during the the invasion of Leyte. On 25 October, at the Battle off Cape Engaño, she met TF.34’s USS New Orleans, USS Wichita, USS Santa Fe and USS Mobile and at least 9 destroyers. Hatsuzuki face them while the remainder of the force withdrew, making back and forth tprpedo and gunnery attack for the next two hours while covering the escape of Zuikaku, Zuihō and Chitose, Wakatsuki, Kuwa and Isuzu, in between. Eventually she was crippled and ssank at 20:59 East-northeast of Cape Engaño. 8 men survived on a lifeboat, with 17 from Zuikaku and landed in Luzon on 14 November.

Niizuki (1942)

Niizuki (108, 新月) was laid down at Mitsubishi-Nagasaki Shipyard on 8 December 1941, launched on 29 June 1942 and commissioned on 31 March 1943. She made her maiden voyage to Sasebo under Command of Kaneda Kiyoshi, for training duties between Sasebo, Kure, and Hashirajima. In April she transited between Japanese ports, including escorting Mogami to Kure after the invasion of Attu Islands. On June 16, Niizuki departed Japan to Saipan but ambushed underway by USS Flying fuckFish, but no ship was damaged and Niizuki arrived before departing for Truk. On 23-25 she escorted a troop transport run to Rabaul. RADM Teruo made her his flagship for DesRon 3. He headed for the central Solomons, Bougainville, Rendova. Midnight saw Niizuki in action with Yubari, shelling US defences with gunfire before retreating but underway she was ambushed by PT-156, PT-157, and PT-161, all six torpedoes missed and she answered by gunfire, claiming two.
On the night of July 4th she sailed to Buin as cover force for a troop transport mission to Kolombangara with Nagatsuki, Satsuki, and Yūnagi, and started to unload men and supplies, until the 5th, when her search radar located an enemy task force, US ships bombaridng Bairoko Harbor. A flotilla scouting ahead of the cruisers went their way, and battle stations commenced under the lead of Niizuki, making an extremely long-range torpedo attack, four each for two, and Yūnagi fired six. Older torpedoes ran out of fuel, but one of Niizuki’s long lance hit USS Strong port side amidships leaving her dead in the water. USS Chevalier evacuate her survivors when shore batteries opened fire. Strong broke apart and sank. This torpedo hit is considered a record, authors evaluating it between 19,000 yards to 22,000 yards, making it the longest torpedo hit in history, on par with Haguro‘s kill on Kortenaer at 22,000 yards.

Then the Japanese retreated. Niizuki afterwards acted as Admiral Teruo’s flagship with Suzukaze and Tanikaze as protection group for seven other destroyers with 2,600 soldiers, 180 tons ammunitions. But they were spotted by allied coast watchers, and ambushed by the same US cruiser-destroyer group encountered the previous night. On 5 July 1943, the battle developed against USS Honolulu, Saint Louis and Helena (Brooklyn class), escort by four DDs, detecting fisr by radar Niizuki, Suzukaze, and Tanikaze. This cruiser force represented a total of 45 rapid firing 6-inch (152 mm) and a dozen 5-inch (127 mm) guns. They rained fire on the lead destroyer at 4,400 yards, hit her with the first salvo and Niizuki caught fire, until she was dead in the water.

She probably retaliated, as the later discovery of her wreck showed she had trained her forward guns, unloading several salvos and a full spread of four torpedoes. Back at the battle, her enhineers managed to regain 11 knots when she was hit by one or two torpedoes from USS Nicholas, which was the finishing blow. She sank around 1:00, with 290 men including Admiral Teruo and Commander Kiyoshi. Perhaps a dozen survived. In between as she concentrated fire, this enabled the two other DDs to hit Helena, notably Suzukaze, severing her bow after a magazine explosion. Helena’s engine, boilers, and keel were broken by more hits and sank with 168 men. The battle of Kula Gulf was taunted back home as a Japanese victory as they also reinforced Kolombangara.
Niizuki’s wreck was discovered by RV Petrel in January 2019 under 745 meters (2,444 feet). No photo survived (like for other DDs here).

Wakatsuki (1942)

Wakatsuki (109, 若月) was laid down at Mitsubishi-Nagasaki Shipyard on 9 March 1942, launched on 24 November 1942 and commissioned on 31 May 1943. She was assigned to the 11th Destroyer Squadron, for training with Tamanami off Hashirajima, escorting the IJN Nagato at the time Mutsu sank in harbor after a magazine detonation, rescuing 353 survivors. On 22 June, she escorted Musashi with the remains of Admiral Yamamoto. Next, Sagara Maru crippled by a torpedo from USS Harder, albeit could not prevent more torpedoes from USS Pompano, which finished her off.
Assigned to the 7th destroyer division with Suzutsuki and Hatsuzuki on 18-25 September she tried to counter the US carrier raids. Same on 17-26 October, and 30 October-1 November was in scort of troop transports Truk-Rabaul. On site she was deployed to repeat a battle of Savo Island style acction that became the battle of the Empress Augusta Bay, on 1-2 November. She participated bt gunfire, but missed and lost contact after near colliding with Haguro. Sendai and Hatsukaze were sunk, ending in an US victory. Air raids on Rabaul left her with near misses. Next she was in troop transports and took part in the sinking of USS Sculpin and in refit at Yokosuka from 25 November to January 1944. She escorted Shōkaku and Zuikaku from Kure to Singapore, and IJN Taihō for the following months, with ASW patrols at Tawi-Tawi. On 6 June she saw Minazuki sunk by USS Harder, and rescue 45 survivors. On 19 June, she took part in the battle of the Philippine Sea, with Taihō, but could not prevent her sinking by USS Albacore, rescuing survivors, and transferring Admiral Ozawa to Haguro.
She was in a troop transport run on 8-20 July from Okinawa to Manila and Lingga, back home on 19 September with a tanker convoy. On 16 October she assisted Suzutsuki, damaged by USS Sturgeon, escorted her to Kure. Next she was prepared for Operation Sho-Go, known in the US as the battle of Leyte Gulf, escorting the decoy aircraft carrier force.
She departed Brunei on 22 October, guarding Zuikaku, Zuihō, Chitose, and Chiyoda, which launched some 120 Kamikaze. In return they were caught by US carrier aircraft, starting the battle of Cape Engano. All four carriers, Tama and Akizuki were sunk or crippled. Wakatsuki evaded all attacks before and rescued survivors from Zuikaku. Chitose, was attempted protected by Hatsuzuki sank by the cruisers. Wakatsuki rescued more survivors and ended jam-packed with men when she returned to Brunei. From 29 October to 1 November she escorted Ōyodo to Manila. On 8 November 1944, with Naganami, Hamanami, Asashimo, and Shimakaze she departed Manila with troop transports to Ormoc when on the 11th, 350 carrier US aircraft fell on them. This was the battle of Ormoc Bay, a one sided massacre. All transports, Naganami, Hamanami, and Shimakaze, went down, before Wakatsuki. He captain showed excellent maneuverability, until sher took a bomb hit on her bow, then stern, ending dead in the water. After many more hits as the remainder of aircraft dumped all their ordnance before going back, she sank bow first with only 45 sailors surviving. Full logs

Shimotsuki (1943)

Battle of Cape Engano: Ise and Shimotzuki trying to dodge dive bombers from USS Enterprise. Note the damage wing of the one (likely a Helldiver) taking the photo.
Shimotsuki (360, 霜月) was laid down at Mitsubishi-Nagasaki Shipyard on 6 July 1942, launched on 7 April 1943 and comissioned on 31 March 1944. In January 1943 her sistership Akizuki was crippled by USS Nautilus so by July, Shimotsuki’s bow was removed up to frame 75, to replace Akizuki’s one. This seriously delayed Shimotsuki’s construction and commission under commander Hatano Kenji. In April-May, she remained off Japan in training and transits, only departing on 10 June for Tawi-Tawi, for the battle of the Philippine Sea, on the 19-20th. She saw the sinking of Taihō and Shōkaku to submarines, and was herself badly damaged by a near miss jamming her steering but claimed two aircraft shot down before heading to Okinawa. Next she headed for Yokosuka and had a modernization.
On 9 July, she wa sin a troop transport run to Manila, as flagship, Wakida Kiichiro DesDiv 21, remaining off Lingga and by August she was on more convoy missions, back in training in September. On 12 October, she assisted Fuyutsuki torpedoed by USS Trepang, and headed for Brunei. On 25 October 1944, she escorted the decoy carrier force at the battle of Leyte Gulf. She assisted the sinking Chitose, escorted Ise and Hyūga. Underway, they were attacked by USS Enterprise dive bombers and Hyūga, Shimotsuki were damaged by near misses.
On the 27th, Shimotsuki was docked for repairs and escorted Hyūga to Kure, both being drydocked. In November 1944 Shimotsuki returned to Manila, and until the end she performed various escorting missions. On 25 November 1944, while in a troop convoy for the defense of Manila, she was detected by USS Cavalla, which launched six torpedoes, four hit the destroyer. This was a tremendous force, she was blasted apart and sank instantly with 290 men and the command staff, Captain Kiichiro and Commander Kenji. 46 men survived, rescued by IJN Momo.

Fuyutsuki (1944)

Fuyutsuki (361, 冬月) was laid down at Maizuru Naval Arsenal 8 May 1943, launched on 20 January 1944 and commissioned on 25 May 1944. She was assigned to the 11th Destroyer Squadron and after a training mission and departed on 24 June to Yokosuka with Landing Ship No. 4 and Landing Ship No. 104. On 25 June, she escorted the I-Gō Transport Squadron. On 29 June, she was deployed to Chichi-jima with IJN Nagara and the escort DD Matsu, back to Yokosuka on 3 July. On 11 July, she sailed to Tokuyama with Kiyoshimo. On 14 July, she joined the Ro-Gō Transport Squadron to Nakagusuku Bay. On 15 July, she was assigned to DesDiv 41st Destroyer Division, DesDiv 10th, 3rd Fleet with her sister Shimotsuki and after some training went back to Kure on 26 July.
On 12 October, while escorting IJN Ōyodo from Yokosuka to the Inland Sea she was torpedoed by USS Trepang. Her bow was nearly severed by the impact and she needed long repairs at Kure.
On 31 January 1945 she ran aground on a sandbar near Ōita (training mission in the Inland Sea) and later she took part in the last mission of Yamato (6–7 April 1945). She had to scuttle the crippled destroyer Kasumi with torpedoes after rescuing the crew. She survived the mission, despite several 127 mm rockets and bombs nar-misses or hits, making 12 killed, 12 injured. On 20 August 1945, while stuck in Japan due to the lack of fuel she hit a mine at Moji, Kyūshū, her stern completely shattered. She surrendered unrepaired and was later used as a breakwater in May 1948 in Wakamatsu-ku, alongside Suzutsuki and Yanagi, under Yanagi’s hull.

Harutsuki (1944)

Harutsuki (362, 春月 “Spring Moon”) was laid down at Sasebo Naval Arsenal on 23 December 1943, launched on 3 August 1944 and commissioned on 28 December 1944. She only was operational in early 1945 but the lack of fuel limited her activities to local waters escort as flagship for the Escort Fleet. She survived the war unscaved. On 5 October 1945, she stricken and on 28 August 1947, turned over to the Soviet Union and renamed Vnezapny, rearmed with 8x 102 mm (4 in) guns, 15x 25 mm guns and 1×4 533-millimeter (21 in) Soviet torpedo tubes. She became the training ship Oskol in 1949. Eventually she ended as the target ship TsL-64 in 1955 and the floating barracks PKZ-37 until scrapped in 1969.

Yoizuki (1944)

Yoizuki (363 宵月) was laid down at Uraga Dock Company on 25 August 1943, launched on 25 September 1944 and commissioned on 31 January 1945. She was commissioned too late to see action in World War II, only training, limited by the general lack of fuel in the Navy. Thus, she surrendered intact. In March, 1946, Yoizuki transported over 1,000 Formosans, Filipinos and Japanese POW from Sydney in Australia to their respective countries. However the conditions aboard and distress of the repatriates sparked controversy in Australia. On 29 August 1947, she was ceded as war reparation to the Republic of China and renamed CNS Fen Yang, active (and flagship of the ROCS for years), until scrapped in 1963.

Natsuzuki (1944)

Natsuzuki (364 夏月) was laid down at Sasebo Naval Arsenal on 1 May 1944 , launched on 2 December 1944 and commissioned on 8 April 1945. She was assigned DesRon 11, 2nd Fleet for training, later transferred to the Combined Fleet on 20 April. Next she was reassigned to DesDv 41, Escort Squadron 31, on 25 May. She was badly damaged when hitting a naval mine on 16 June and repaired at Sasebo Naval Arsenal. She was then turned over to Allied forces at Moji as Japan surrendered on 2 September, stricken from list on 5 October. Disarmed she was used to repatriate Japanese troops from scaretted garrison across the former Empire, and notably all the gorgotten islands and outpost never “visited” by the US forces in the hopping campaign. On 25 August 1947, she was ceded as war reparation to Great Britain which had it scrapped by Uraga Dock Co. (Kanagawa) from 1 March 1948.

Michitsuki (never)

Michitsuki (365 満月) was laid down at Sasebo Naval Arsenal on 3 January 1945. She was only 16% complete when construction was stopped on 17 April 1945. She was scrapped on 28 February 1948.

Hanazuki (1944)

Hanazuki (366 花月) was laid down at Maizuru Naval Arsenal on 10 February 1944, launched on 10 October 1944 and commissioned on 26 December 1944. He full logs will be written here for the post update in 2027 or 2028. However her service was limited to the Japanese home waters due to the lack of fuel localescorts and patrol, then static AA defence. She was unscaved, surrendered in September, and by June 1947, turned over to the US as “DD-934”. The latter decied to test her with various new weapons being developed then, and she was sunk as target off Gotō Islands, on 3 February 1948.

Hanatsuki postwar with peacetime markings and partially disarmed, used as repatriaiton vessel.