Japanese battleship Kawachi The was the lead ship of the two - ship dreadnought battleship s built for the Imperial Japanese Navy ( IJN ) in the first decade of the 20th century . Following the Japanese ship - naming conventions , " Kawachi " was named after Kawachi Province , now a part of Osaka prefecture . During World War I she bombarded German fortifications at Tsingtao during the Battle of Tsingtao in 1914 , but saw no other combat . She sank in 1918 after an explosion in her ammunition magazine with the loss of over 600 officers and crewmen . Background . The " Kawachi " class was ordered on 22 June 1907 under the 1907 Warship Supplement Program after the Russo - Japanese War as Japan ' s first dreadnoughts , although their construction was delayed by a severe depression . Their design was based on the with a uniform main - gun armament , although cost considerations prevented all the guns from having the same barrel length . Design and description . The ship had an overall length of , a beam of , and a normal draft of . She displaced at normal load . Her crew ranged from 999 to 1100 officers and enlisted men . " Kawachi " was fitted with a pair of license - built Curtis steam turbine sets , each set driving one propeller , using steam from 16 Miyabara water - tube boilers . The turbines were rated at a total of for a design speed of . She carried enough coal and fuel oil to give her a range of at a speed of . " Kawachi " s main armament consisted of four 50 - caliber 12 - inch 41st Year Type guns in two twin - gun turret s , one each fore and aft of the superstructure , and eight 45 - caliber 12 - inch 41st Year Type guns mounted in four twin - gun turrets , two on each side of the superstructure . " Kawachi " s secondary armament was ten 45 - caliber 6 - inch 41st Year Type guns , mounted in casemate s in the sides of the hull , and eight 40 - caliber quick - firing ( QF ) 4 . 7 - inch 41st Year Type guns . The ship was also equipped with a dozen 40 - caliber 3 - inch 4th Year Type guns and four others were used as saluting gun s . In addition , the battleship was fitted with five submerged torpedo tube s , two on each broadside and one in the stern . The waterline main belt of the ship had a maximum thickness of 12 inches amidships . It tapered to a thickness of at the ends of the ship . A strake of armor protected the casemates . The barbettes for the main guns were thick . The armor of " Kawachi " s main gun turrets had a maximum thickness of 11 inches . The deck armor was thick and the conning tower was protected by 6 to 10 inches of armor . Construction and career . " Kawachi " , named for Kawachi Province , was laid down at Yokosuka Naval Arsenal on 1 April 1909 . She was launched on 15 October 1910 and completed on 31 March 1912 at a cost of ¥ 11 , 130 , 000 . On 3 October 1912 , the ship was present when the battleship had a fire that was started by a sailor in the forward magazine . It was flooded before the fire could get out of control and " Kawachi " sent over fire - fighting teams to assist " Mikasa " s crew in case they were needed . When World War I began in August 1914 , " Kawachi " was at Yokosuka . Together with her sister ship , , she bombarded German fortifications in October – November 1914 during the final stage of the Battle of Tsingtao . The ship was present in Yokosuka on 8 January 1915 when the victorious Second Squadron returned to Japan after the Battle of Tsingtao . She was assigned to the First Squadron from 1915 – 1917 and refitted that latter year . " Kawachi " rejoined the First Squadron after her refit and entered Tokuyama Bay on the evening of 11 July 1918 . The following morning torpedo target practice was cancelled due to rough seas and the battleship remained at anchor for the rest of the day . That afternoon a loud explosion was heard at 15 : 51 in the vicinity of the starboard forward main - gun turret and large quantities of smoke erupted from the turret and between the first and second funnels . Two minutes later , she began to list to starboard and capsized at 15 : 55 , only four minutes after the explosion . Over a thousand men were aboard Kawachi at the time of the explosion and over 600 of them were killed , with 433 survivors . The IJN convened a commission to investigate the explosion the day after the incident with Vice Admiral Murakami Kakuichi as chairman . It first suspected arson , but no logical suspect could be found and it reported that the cordite in the magazine might have spontaneously ignited due to decomposition . " Kawachi " s magazines had been inspected in January – February 1918 , however , and no problems were discovered , which made that possibility less likely . The commission made recommendations on tighter control of production and handling of cordite that were successfully adopted by the navy . The IJN considered salvaging " Kawachi " , but ultimately decided that it would be too expensive and would delay the construction of one battlecruiser by over a year . Stricken from the Navy List on 21 September 1918 , the wreck was later partially dismantled although most of the hull was abandoned in place to serve as an artificial reef .