Japanese Cruisers at the Battle of The Java Sea

In May 1937 Ashigara represented Japan in the Coronation Review for King George VI. Afterwards she paid a goodwill visit to Germany. In the course of this tour she became the most heavily photographed member of the class.

The two forward turrets and the tower bridge of Haguro are shown in this photograph from March 1941. The ship has completed her Second Modernisation and the upward slanting yardarms on the new tripod foremast are clearly shown. Under orders to reach peak efficiency by July 1941, Japanese warships significantly changed appearance in this period. Gone were the light natural canvas dodgers and main gun blast bags, which contrasted so smartly with the grey of the paint scheme, in favour of much less visible brown stained canvas.


This is the tower bridge of Haguro in March 1941. The ship has already taken on a wartime appearance. Canvas dodgers, originally left in natural canvas colour, and the rope-filled canvas bags for additional splinter protection are now dyed a light to mid brown, as were the blast bags for the main guns.


In July 1922, after Japan had signed but not ratified the Washington Treaty, a new naval program proposed four new 10,000-ton cruisers, as well as two more 7,500-ton cruisers, which was the Aoba class. Authorised in March 1923 the new 10,000-ton design was known officially as large model cruisers. The original requirement was for eight 200mm guns in three twin mounts forward and one twin mount aft, four 120mm (4.7in) guns, eight 610mm torpedo tubes in four twin fixed mountings, protection against 200mm shells in indirect fire and 6in shells for flat trajectory direct fire for critical areas, a 10,000 nautical mile range at 13.5 knots, and a maximum speed of 35.5 knots. Captain Hiraga Yuzuru was assigned as Constructor for the design. Captain Hiraga convinced the naval staff to make some changes to the requirements. These were an increase in main armament to ten 200mm guns, reduction of range to 8,000nm at 13.5 knots and deletion of torpedo armament. Captain Hiraga thought the torpedo mounts, located inside the hull above the engine spaces, would present as much danger to the ships themselves as to the enemy. Hiraga was promoted to Rear Admiral and Lieutenant Commander Fujimoto Kikuo took over the design. The design was approved on 23 August 1923. The new cruisers were to be 10,000 tons standard in English tons, 11,850 metric tons at 2/3 trial displacement, so the original construction order had the ships meeting the terms of the Washington Treaty.

However, additions were quickly made to the design, each of which added weight. The Torpedo Branch convinced the Naval General Staff to add back the four twin tube torpedo armament and the staff increased the secondary to six 120mm HA single gun mounts. While the ships were under construction the twin tubes were changed to triple tubes and in 1928 a deckhouse on either side of the bridge and forward stack was added for additional living accommodation. The Naval General Staff calculated that these changes would add 500 metric tons and that the revised 2/3 trial displacement would be 12,350 metric tons. Since the original design was right at the treaty limit, the staff knowingly exceeded treaty limitations with these additions. Called the Myoko class, the first of the cruisers to complete was Nachi. The trial displacement of Nachi was 13,338 metric tons, which was 12% over design trial displacement. This would place the ship at about 11,250 tons standard, clearly in violation of treaty limits. Of course the Japanese reported the design as in compliance with the treaty.

As built the Myoko class had an armour belt of 102mm in thickness and inclined inward at 12 degrees. The belt started forward of No 1 barbette and ended aft of No 5 barbette. For torpedo and mine protection, the ship was fitted with underwater bulges that were 300 feet (93m) long and 8 feet (2.5m) in depth. They were to be left as a void but in case of war, watertight steel tubes would occupy the space. Since the cruisers were 12% over designed displacement, other design calculations were out of kilter as well. Draft was increased by almost 4ft (1.2m), so amidships only 6ft (1.8m) of the belt was above the waterline and only 1ft (0.3m) at the bow and stern. In any sort of seaway any battle damage to the hull could entail a significant intake of water.

The ten Type 3 20cm/50 main guns were capable of 40 degrees elevation with a maximum range of 26,700m. The main gun turrets were more gun houses than turrets as they were armoured by only 1in (25.4mm) plates. They were proof against splinters but not against 6in shell strikes. On completion the Nachi carried her six 4.7in (120mm) secondary guns in open, hand-operated mounts, but these were quickly replaced with power-operated mounts with gun shields. The catapult was offset to starboard of centreline on the quarterdeck level, just forward of the aft turrets. Although the requirements were for the ship to carry two floatplanes, only one Type 15 seaplane was carried by the ships in the class until November 1932. To reach the designed speed of 35.5 knots a power plant generating 130,000shp was installed. It is interesting to note that the Japanese ran the ships in light condition for their speed trials. Instead of running at the stipulated 2/3 trial displacement, which would have been around 13,300 tons, they were actually tested at a displacement of 12,350 metric tons. This would be far less than their operational displacement, and in this unrealistically light condition all four cruisers attained 35 knots, but only Nachi and Haguro exceeded the designed 35.5 knots.

Battle of The Java Sea

The Dutch East Indies were the major prize for which Japan had gone to war. With the pre-war oil embargo against Japan strangling Japanese fuel supplies, the Japanese government saw the capture of the oil fields of Borneo and the Dutch East Indies as essential to make their country self-sufficient. The northern barriers to the Java Sea, Borneo and the Celebes, surrendered in January 1942, and operations against Java and the rest of the Dutch possessions began. The Japanese planned a double envelopment of the islands. The 5th Cruiser Squadron was assigned the mission of covering force for the eastern invasion force.

Opposing the Japanese naval force was a polyglot allied force of American, British, Dutch and Australian warships entitled the ABDA Combined Force. Established on 10 January 1942 ABDA’s organisation and communications were appallingly poor and in the event only provided targets for the extremely well prepared and coordinated Japanese attack on the islands. On 3 February 1942 the bulk of the allied warships still operational in the area were placed under the command of Dutch Rear Admiral Karel Doorman.

Nachi was the flagship of Vice Admiral Takeo Takagi, commander of Main Body, Eastern Invasion Support Force. The 5th Cruiser Squadron was down to just Nachi and Haguro, as Ashigara was acting as flagship for Vice Admiral Ibo Takahashi, overall Southern Force commander, and the Myoko was at Sasebo for repairs. The eastern invasion force sailed on 19 February but their southward passage was not confirmed by ABDA command until 24 February. Admiral Doorman’s strike force consisted of the heavy cruisers HMS Exeter and USS Houston, the Dutch light cruisers, Java and De Ruyter, along with HMAS Perth. With minimal reconnaissance the allied force started making a series of sweeps in an effort to find Japanese troop convoys, and on 27 February it ran into the Japanese screening forces.

On paper the two forces looked fairly closely matched. In addition to the two heavy and three light cruisers, Doorman’s force also had nine destroyers – four American, three British and two Dutch. Facing them were three groups of Japanese forces. One group was the light cruiser Jintsu and four destroyers. Another was the light cruiser Naka and six destroyers. Furthest north of the Japanese forces were Nachi and Haguro, along with another four destroyers. However, the allies only had a total of twelve operational 8in guns as Exeter had only three twin turrets and Houston had only her two forward turrets in operation (Houston’s aft turret had been wrecked by a bomb earlier in the month). The forces sighted each other around 15.21 and one of the rarities of the Pacific War occurred: a daylight surface engagement in which aircraft played a minimal role.

In the first of a series of engagements, Nachi scored a serious hit on Exeter setting her on fire. Two minutes later, a Long Lance torpedo from Haguro blew up the Dutch destroyer Kortenaer. Doorman turned his force away from the Japanese; the Exeter, down to 5 knots and screened by the one Dutch and three British destroyers, separated.

At 17.20 it appeared to Doorman that the Japanese forces were retiring, so he reversed course in another effort to get at the transports, but at 17.28 the Japanese light cruisers with their destroyers altered course towards the Exeter group, and the destroyer HMS Electra was hit twice and sank at 17.46. The forces lost sight of each other and it appeared that the battle was over. After some time passed, Doorman made his third attempt to find and attack the Japanese troop transports. At 18.50 contact was restored and Java, Houston, Perth and De Ruyter, with one British and four American destroyers engaged in a harmless skirmish with the Japanese Nachi, Haguro, Jintsu and eight destroyers before contact was again broken.

HMS Jupiter was lost when she ran into a mine and Doorman detached his four American destroyers to return to port to refuel. So at 22.33 when the Nachi, Haguro, Jintsu and eight destroyers regained contact with the allies there were just the Houston and three light cruisers left in the allied force. Long range gunfire failed to hit on either side but then the Japanese fired more torpedoes, eight from Nachi and four from Haguro. As they would continue to prove through 1942 and 1943, the 24in Japanese Long Lance torpedoes were the battle winners for the Japanese Navy. One hit De Ruyter and she soon sank, taking Admiral Doorman with her. In a few minutes another struck Java and she quickly followed. The surviving Houston and Perth broke contact and headed back to Batavia, while the Exeter, Encounter and US destroyer Pope were at Surabaya.

On the evening of 28 February the Exeter force put to sea again with orders to escape to Ceylon. On 1 March the crippled HMS Exeter and her two destroyers were trapped between all four members of the Myoko class, the Ashigara and Myoko to the north and the Nachi and Haguro to the south. Torpedoes from either or both Nachi and Haguro struck Exeter and she sank at 11.30. At 11.35 Encounter went down due to hits from Ashigara and Myoko. The USS Pope was the last to go, when she too succumbed to overwhelming fire at around 12.05. The Battle of the Java Sea had lasted two days and was an overwhelming victory for the Japanese Navy. The Myoko class cruisers were the key Japanese components in the battle, and although their gunnery at long range had been unimpressive, there is no doubt about the value of their heavy torpedo battery.

Although Chokai was with the Suzuya and Kumano in the 7th Cruiser Squadron, the other three Takao class cruisers still made up the 4th Squadron, supporting the western pincer against Java. Maya and two destroyers encountered and sank the destroyer HMS Stronghold on March 2, and Takao and Atago sank the old four-stack destroyer USS Pillsbury; it took only seven minutes.


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