'Peaceful Seas') was a light cruiser in the Republic of China Navy (ROCN) before World War II and the lead ship of her class.

Despite the very strained political relations between Japan and China and the strenuous objections of the Japanese military, Harima Shipyards completed the first cruiser in 1932.

Ning Hai was based on the experimental Japanese cruiser Yūbari, which combined a small size with heavy weaponry, but in an even smaller displacement of only 2,526 t (2,486 long tons).

Ning Hai also had a small hangar for two seaplanes; two Aichi AB-3 biplanes, one bought from Japan and one built locally using a spare engine and domestic materials, were assigned to it.

However, the vessel was underpowered, with three antiquated vertical four-cylinder triple-expansion steam engines, two of which were coal-fired, yielding a top speed of only 22 knots.

[2] In December 1943, with Japanese maritime traffic under increasing pressure from Allied submarine warfare, Mikura was towed to the Harima Shipyards for reconstruction into a "Kaibōkan" (escort ship).