She was laid down in 1941 at the Droogdok Maatschappij Soerabaja as an auxiliary minelayer for the benefit of the Gouvernementsmarine and named Regulus.

[3] On 21 September 1944, Nankai departed Surabaya, Java escorting transport Hokkai Maru.

[5] On 23 September 1944, Nankai and Hokkai Maru both strike mines[6][5] laid by the submarine USS Bowfin, 15 miles west of Sebuku Island at 03°37′S 116°25′E / 3.617°S 116.417°E / -3.617; 116.417.

[7] On 16 July 1945, while being escorted by No.1-class submarine chaser CH-1,[8] she was torpedoed and sunk by the USS Blenny at 05°26′S 110°33′E / 5.433°S 110.550°E / -5.433; 110.550, 150 miles west of Surabaya.

[2] This article about a specific military ship or boat of Japan is a stub.