(sometimes transliterated (archaically) as Adzuma) was an armored cruiser (Sōkō jun'yōkan) built for the Imperial Japanese Navy (IJN) in the late 1890s. As Japan lacked the industrial capacity to build such warships itself, the ship was built in France. She participated in most of the naval battles of the Russo-Japanese War of 1904–05 and was lightly damaged during the Battle off Ulsan and the Battle of Tsushima. Azuma began the first of five training cruises in 1912 and saw no combat during World War I. She was never formally reclassified as a training ship although she exclusively served in that role from 1921 until she was disarmed and hulked in 1941. Azuma was badly damaged in an American carrier raid in 1945, and subsequently scrapped in 1946.
Background and design The 1896 Naval Expansion Plan was made after the First Sino-Japanese War, and included four armored cruisers in addition to four more battleships, all of which had to be ordered from overseas shipyards as Japan lacked the capability to build them itself. Further consideration of the Russian building program caused the IJN to believe that the battleships ordered under the original plan would not be sufficient to counter the Imperial Russian Navy. Budgetary limitations prevented ordering more battleships and the IJN decided to expand the number of more affordable armored cruisers to be ordered from four to six ships, believing that the recent introduction of tougher Krupp cemented armor would allow them to stand in the line of battle. The revised plan is commonly known as the "Six-Six Fleet". The first four ships were built by Armstrong Whitworth in the United Kingdom, but the last two ships were built in Germany and France. To ensure ammunition compatibility, the IJN required their builders to use the same British guns as the other four ships.Evans & Peattie, pp. 57–62 In general, the IJN provided only a sketch design and specifications that each builder had to comply with; otherwise each builder was free to build the ships as they saw fit. Unlike most of their contemporaries which were designed for commerce raiding or to defend colonies and trade routes, Azuma and her half-sisters were intended as fleet scouts and to be employed in the battleline.Milanovich, p. 72
Description
The ship was long overall and between perpendiculars. She had a beam of and had an average draft of . Azuma displaced at normal load and at deep load. The ship had a metacentric height of . She had a double bottom and her hull was subdivided into 213 watertight compartments.Milanovich, pp. 74, 80 Her crew consisted of 670 officers and enlisted men.Jentschura, Jung & Mickel, p. 73
Azuma had two 4-cylinder triple-expansion steam engines, each driving a single propeller shaft.Milanovich, p. 81 Steam for the engines was provided by 24 Belleville boilers and the engines were rated at a total of . The ship had a designed speed of . She carried up to of coal and could steam for at a speed of .Jentschura, Jung & Mickel, pp. 73–74
Armament The main armament for all of the "Six-Six Fleet" armored cruisers was four Armstrong Whitworth-built 45-caliber eight-inch guns in twin-gun turrets fore and aft of the superstructure. The electrically operated turrets were capable of 130° rotation left and right, and the guns could be elevated to +30° and depressed to −5°. The turret accommodated 65 shells, but could only be reloaded through doors in the turret floor and the ship's deck that allowed the electric winch in the turret to hoist shells up from the shell room deep in the hull.Milanovich, pp. 76–77 The guns were manually loaded and had a rate of fire about 1.2 rounds per minute. The 203-millimeter gun fired armor-piercing (AP) projectiles at a muzzle velocity of to a range of .Milanovich, p. 78
The secondary armament consisted of a dozen Elswick Ordnance Company "Pattern Z" quick-firing (QF), 40-caliber, 6-inch guns. All but four of these guns were mounted in armored casemates on the main and upper decks, and their mounts on the upper deck were protected by gun shields. Their AP shells were fired at a muzzle velocity of .Friedman, p. 276; Milanovich, p. 78 Azuma was also equipped with a dozen 40-caliber QF 12-pounder 12-cwt guns"Cwt" is the abbreviation for hundredweight, 12 cwt referring to the weight of the gun. and eight QF 2.5-pounder Yamauchi guns as close-range defense against torpedo boats. The former gun fired , projectiles at a muzzle velocity of .Friedman, p. 114
Azuma was equipped with five torpedo tubes, one above water in the bow and four submerged tubes, two on each broadside. The Type 30 torpedo had a warhead and three range/speed settings: at , at or at .Milanovich, p. 80
Armor All of the "Six-Six Fleet" armored cruisers used the same armor scheme with some minor differences, one of which was that the four later ships all used Krupp cemented armor. The waterline belt ran the full length of the ship and its thickness varied from amidships to at the bow and stern. It had a height of , of which was normally underwater. The upper strake of belt armor was thick and extended from the upper edge of the waterline belt to the main deck. It extended from the forward to the rear barbette. Azuma had only a single transverse 76 mm armored bulkhead that closed off the forward end of the central armored citadel.Milanovich, pp. 80–81
The barbettes, gun turrets and the front of the casemates were all 152 millimeters thick while the sides and rear of the casemates were protected by of armor. The deck was thick and the armor protecting the conning tower was in thickness.Chesneau & Kolesnik, p. 225
Construction and career The contract for Azuma, named after the Kantō region,Silverstone, p. 326 was signed on 12 October 1897 with Ateliers et Chantiers de la Loire, and the ship was laid down at their shipyard in Saint-Nazaire on 1 February 1898. She was launched on 24 June 1898 and completed on 29 July 1900. Azuma left for Japan the next day and arrived in Yokosuka on 29 October.Milanovich, p. 73 Captain Fujii Kōichi assumed command before the start of the Russo-Japanese War in February 1904, until he was relieved in January 1905Kowner, p. 125 by Captain Murakami Kakuichi.Corbett, II, p. 153
Russo-Japanese War At the start of the Russo-Japanese War, Azuma was assigned to the 2nd Division of the 2nd Fleet.Kowner, p. 465 She participated in the Battle of Port Arthur on 9 February 1904, when Vice Admiral Tōgō Heihachirō led the Combined Fleet in an attack on the Russian ships of the Pacific Squadron anchored just outside Port Arthur. Tōgō had expected the surprise night attack by his destroyers to be much more successful than it was, anticipating that the Russians would be badly disorganized and weakened, but they had recovered from their surprise and were ready for his attack. The Japanese ships were spotted by the protected cruiser , which was patrolling offshore and alerted the Russians. Tōgō chose to attack the Russian coastal defenses with his main armament and engage the ships with his secondary guns. Splitting his fire proved to be a poor decision as the Japanese eight- and six-inch guns inflicted little damage on the Russian ships, which concentrated all their fire on the Japanese ships with some effect.Forczyk, pp. 42–43 Although many ships on both sides were hit, Russian casualties numbered some 150, while the Japanese suffered roughly 90 killed and wounded before Tōgō disengaged.Corbett, I, p. 105
In early March, Vice Admiral Kamimura Hikonojō was tasked to take the reinforced 2nd Division north and make a diversion off Vladivostok. While scouting for Russian ships in the area, the Japanese cruisers bombarded the harbor and defenses of Vladivostok on 6 March to little effect. Upon their return to Japan a few days later, the 2nd Division was ordered to escort the transports ferrying the Imperial Guards Division to Korea and then to join the ships blockading Port Arthur. Kamimura was ordered north in mid-April to cover the Sea of Japan and defend the Korea Strait against any attempt by the Vladivostok Independent Cruiser Squadron, under the command of Rear Admiral Karl Jessen, to break through and unite with the Pacific Squadron. The two units narrowly missed each other on the 24th in heavy fog, and the Japanese proceeded to Vladivostok, where they laid several minefields before arriving back at Wonsan on the 30th.Corbett, I, pp. 138–39, 142–45, 160, 177, 188–89, 191–96
The division failed to intercept the Russian squadron as it attacked several transports south of Okinoshima Island on 15 June, due to heavy rain and fog. The Russians sortied again on 30 June, and Kamimura finally was able to intercept them the next day near Okinoshima. The light was failing when they were spotted and the Russians were able to disengage in the darkness. Jessen's ships sortied again on 17 July, headed for the eastern coast of Japan to act as a diversion and pull Japanese forces out of the Sea of Japan and the Yellow Sea. The Russian ships passed through Tsugaru Strait two days later and began capturing ships bound for Japan. The arrival of the Russians off Tokyo Bay on the 24th caused the Naval General Staff to order Kamimura to sail for Cape Toi Misaki, Kyūshū, fearing that Jessen would circumnavigate Japan to reach Port Arthur. Two days later he was ordered north to the Kii Channel and then to Tokyo Bay on the 28th. The General Staff finally ordered him back to Tsushima Island on the 30th; later that day he received word that Jessen's ships had passed through the Tsugaru Strait early that morning and reached Vladivostok on 1 August.Corbett, I, pp. 283–89, 319–25, 337–51
Battle off Ulsan
On 10 August, the ships at Port Arthur attempted a breakout to Vladivostok, but were turned back in the Battle of the Yellow Sea. Jessen was ordered to rendezvous with them, but the order was delayed. His three armored cruisers, , , and , had to raise steam, so he did not sortie until the evening of 13 August. By dawn he had reached Tsushima, but turned back when he failed to see any ships from the Port Arthur squadron. north of the island he encountered Kamimura's squadron, which consisted of four modern armored cruisers, , , , and Azuma. The two squadrons had passed during the night without spotting one another and each had reversed course around first light. This put the Japanese ships astride the Russian route to Vladivostok.Brook, pp. 34, 37
Jessen ordered his ships to turn to the northeast when he spotted the Japanese at 05:00 and they followed suit, albeit on a slightly converging course. Both sides opened fire around 05:23 at a range of . The Japanese ships concentrated their fire on Rurik, the rear ship of the Russian formation. She was hit fairly quickly and began to fall astern of the other two ships. Jessen turned southeast in an attempt to open the range, but this blinded the Russian gunners with the rising sun and prevented any of their broadside guns from bearing on the Japanese. About 06:00, Jessen turned 180° to starboard in an attempt to reach the Korean coast and to allow Rurik to rejoin the squadron. Kamimura followed suit around 06:10, but turned to port, which opened the range between the squadrons. Azuma then developed engine problems and the Japanese squadron slowed to conform with her best speed. Firing recommenced at 06:24 and Rurik was hit three times in the stern, flooding her steering compartment; she had to be steered with her engines. Her speed continued to decrease, further exposing her to Japanese fire, and her steering jammed to port around 06:40.Brook, pp. 39, 43