Aoba class: twin turrets, common machinery, and range

The Aoba class was built around twin turrets from the start and displaced more than contemporary American estimates suggested. Its protection included a 3-inch belt and an armoured deck, while later fits added a second floatplane and extensive Type 96 light anti-aircraft guns. Japan reused a broadly common machinery layout, increasing power through improved boiler pressure without requiring wholly new engine-room arrangements. The class's 4.7-inch gun also appears as a promising weapon that Japan did not develop far enough for wartime air defence. Later changes traded some top speed for greater range, another sign of the competing demands carried by these cruisers. Aoba ended under air attack at Kure in July 1945, while Kinugasa was sunk during the Guadalcanal campaign in November 1942.