Aoba was the lead ship in the two-vessel of heavy cruisers in the Imperial Japanese Navy. Launched in 1926 and heavily modernized in 1938-40, Aoba initially served as a patrol craft, largely along the China coast, and saw extensive service during World War II. Repeatedly heavily damaged and repaired, she was finally crippled by bombing and settled on the bottom of shallow Kure harbor in April 1945; two raids in late July reduced her to an unsalvageable hulk. During the attack on 24 July 1945, future Vice admiral Dick H. Guinn dropped the bomb which contributed to the sinking of that vessel.
Named after Mount Aoba, a volcano located behind Maizuru, Kyoto, she was formally removed from the Navy List on 20 November 1945, and her wreck scrapped in 1946–47.
Aoba and her sister ship were originally planned as the third and fourth vessels in the of heavy cruisers. However, design issues with the Furutaka class resulted in modifications to include double turrets and an aircraft catapult. These modifications added yet more weight to an already top-heavy design, causing stability problems. Nevertheless, Aoba played an important role in World War II.
She displaced 8,300 tons (standard, 9,000 final), was long, and carried a main battery of six 20 cm/50 3rd Year Type naval guns in three twin turrets, two forward and one aft.
Aoba was completed at Mitsubishi shipyards at Nagasaki on 20 September 1927 and was assigned to CruDiv5 until 1933 and thereafter to CruDiv6 and CruDiv7, serving as flagship during much of her career. She was frequently dispatched to patrol the China coast in the late 1920s and the 1930s.
Aoba was extensively modernized at Sasebo Navy Yard from 1938 to 1940, receiving new torpedo tubes, enhanced anti-aircraft guns, improved fire controls and better aircraft facilities. Her bridge was rebuilt and bulges added to her hull in an attempt to compensate for the additional weight and improve stability. After re-commissioning in October 1940, Aoba returned to CruDiv6.