The Aoba-class is preceded by the Furutaka-class cruiser, because of the changing on design, so this two ships were listed as Aoba-class alone. In 1937, Aoba-class was proceed a large scale modification. During the war, Aoba- class and Furutaka -class were formed into the same troop. In the battle on Oct 1942, Aoba mistakenly treated U-navy as allies, and sent the signal" I am Aoba", then was shot by U-navy. Under the cover of allies, Aoba luckly escaped. However Furutaka was sunk, because of this. In 1944, Aoba was attacked by submarine, then got back to J-country, and never returned to the battle field. When J-country surrended , Aoba was self-sunk in the port.