The Ning Hai-class were a quartet of light cruisers in the Chinese fleet before World War II. Ning Hai the lead ship of the class, was laid down in Japan while the follow-ons, Ping Hai, King Yuan, and Lai Yuan were laid down in China and completed with Japanese assistance to a slightly modified design that included the deletion of seaplane facilities (Ning Hai had a small hangar for two seaplanes). While Ning Hai was quickly commissioned, tensions between China and Japan plagued the efforts to the remaining three ships. The first two ships served as flagships of the Republic of China Navy, with Ping Hai taking over the role from its older sister ship since April 1937. The ROCN had an ambitious plan to procure a larger and more-powerful command cruiser and then to reassign the two vessels as scouts/flagships of submarine flotillas, but the outbreak of war with Japan put an end to all related efforts (including the acquisition of submarines).
Ning Hai and Ping Hai were sunk in defense of the Kiangyin Fortress, Yangtze River, near Nanking by Japanese aircraft (of which the two ships shot down four) on September 23, 1937, but then refloated by the Japanese. Both vessels would be transferred to the puppet government of Wang Jing-Wei in 1940. The King Yuan and Lai Yuan would escape to Australia where they became the flagships of the Free China Navy.