They were intended to reinforce Japan's "eight-eight fleet" of eight battleships and eight battlecruisers after the United States announced a major naval construction program in 1919.

However, after the signing of the Washington Naval Treaty in 1922, work on the ships was suspended; one pair was cancelled in November 1923 and the other in April 1924.

However, having four large battleships (two each of the Nagato and Tosa classes) and four Amagi-class battlecruisers on order put an enormous financial strain on Japan, which was spending about a third of its national budget on the Navy.

The turbines were designed to produce a total of 131,200 shaft horsepower (97,800 kW), using steam provided by 19 Kampon oil-fired water-tube boilers, to reach a maximum speed of 29.75 knots (55.10 km/h; 34.24 mph).

The manually operated guns had a maximum range of 19,750 meters (21,600 yd) at an elevation of +35° and fired at a rate up to 10 rounds per minute.

[5] The ships would have been protected by a waterline belt of armor 292 millimeters (11.5 in) thick, sloped 15° outwards at the top to increase its ability to resist penetration at short range.

The ships' keel laying was stopped on 5 February because the terms of the Washington Naval Treaty that forbade the construction of all battleships over 35,000 long tons (36,000 t).