Tosa (土佐) was a planned battleship of the Imperial Japanese Navy. Designed by Yuzuru Hiraga, she was envisioned as the lead ship of the Tosa class of two 39,900-long-ton (40,540 t) ships. The battleships would have been armed with ten 410 mm (16.1 in) guns and brought Japan closer to its goal of an "Eight-four" fleet. All work on the ship was halted after the Washington Naval Conference and the signing of the Washington Naval Treaty. As the vessel had to be destroyed in accordance with the terms of the treaty, the incomplete Tosa was then subjected to tests to gauge the effect of Japanese weaponry before being scuttled on 9 February 1925.
Tosa at Nagasaki on 31 July 1922; the ship is only complete up to the main deck, hence the lack of any superstructure aside from the small bridge
Tosa's launch, 18 December 1921
Tosa being towed from Nagasaki on 1 August 1922
Tosa sinking stern-first, 9 February 1925.
The Tosa-class battleships were two dreadnoughts ordered as part of the "Eight-Eight" fleet for the Imperial Japanese Navy (IJN) during the early 1920s. The ships were larger versions of the preceding Nagato class, and carried an additional 41-centimeter (16.1 in) twin-gun turret. The design for the class served as a basis for the Amagi-class battlecruisers.
Scale model of Kaga as originally designed
A 41 cm gun on display at the Yamato Museum in Kure, Japan
Tosa, partly complete, being towed from Nagasaki in 1922
Kaga, seen from the stern, under construction in Yokosuka naval yard in November 1928; note the large pipe that directed exhaust smoke down, away from any landing aircraft
