Yūbari (夕張) was an experimental light cruiser built during the early 1920s for the Imperial Japanese Navy (IJN) to test new concepts for reducing the hull's weight while strengthening it. Designs pioneered on Yūbari had a major impact on future Japanese warship designs. Completed in 1923, the ship was generally used as the flagship for destroyer squadrons. She spent large portions of her peacetime career in reserve or used as a training ship. The ship participated in the First Shanghai Incident in 1932 and the Second Sino-Japanese War in 1937 before World War II. During the war Yūbari was the flagship of the forces involved in the Battle of Wake Island and was then sent south to support the invasion of Rabaul in early 1942. She played a small role during the Battle of the Coral Sea as the flagship of the forces intended to invade Port Moresby, New Guinea. At the beginning of the Solomon Islands campaign, Yūbari escorted the forces that made the initial landings on the island of Guadalcanal in July. A few days after the Americans attacked the island in August, the ship participated in the Battle of Savo Island where she crippled an American heavy cruiser and a destroyer.