Kawachi (河内) was the lead ship of her class of two Kawachi-class dreadnought battleships built for the Imperial Japanese Navy (IJN) in the 1910s.

[1] They were ordered on 22 June 1907 under the 1907 Warship Supplement Program after the Russo-Japanese War of 1904–1905, although their construction was delayed by a severe depression.

They carried enough coal and fuel oil to give them a range of 2,700 nautical miles (5,000 km; 3,100 mi) at a speed of 18 knots (33 km/h; 21 mph).

[6] Their secondary armament comprised ten 45-caliber 6-inch (152 mm) 41st Year Type guns, mounted in casemates in the sides of the hull.

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.

[12] Under the command of the newly appointed Captain Masaki Yoshimoto,[16] Kawachi was assigned to the Second Squadron of the First Fleet on 1 December 1917 and became the flagship of Rear Admiral Chisaka Chijirō [ja].

[17] On the evening of 11 July, Kawachi entered Tokuyama Bay, the following morning torpedo target practice was cancelled due to rough seas and the battleship remained at anchor for the rest of the day.

[18][Note 1] The Imperial Japanese Navy convened a commission to investigate the explosion the day after the incident, with Vice Admiral Murakami Kakuichi as chairman.

The Japanese Navy considered salvaging Kawachi, but decided not to do so as the diversion of resources would have delayed the construction of an Amagi-class 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.