Designed for service on Chinese rivers, they were an improved version of the Seta class.

[1][a] The gunboats were powered by a triple expansion engine fed steam by two Kampon boilers turning two shafts creating 970 kW (1,300 ihp).

[2] Both gunboats sailed from Japan to China for service on the Yangtze River.

[3][4] The 11th Gunboat Division evacuated Japanese civilians from interior China to Shanghai in August.

On 13 August, the division landed additional troops during the Second Battle of Shanghai and bombarded shore positions.

[1][2] On 10 June 1943, Atami was damaged by Chinese aircraft on the Yangtze River near Tung Ting Lake.