The was a type of oiler from Japan, serving during the 1930s and World War II. They do not have an official class name.Iino Lines called Tōa Maru class, Kawasaki Line called Tatekawa Maru class, Nittō Mining called Nichiei Maru class, and more... Therefore, this article uses common class names. And, this type has some variants. This article handles them collectively.

Background

The London Naval Treaty forced shrinkage of a budget to the Imperial Japanese Navy (IJN). And it meant the cooling of the Japanese shipbuilding industry worlds. The Great Depression accelerated it more. The IJN wanted to update their Notoro-class oilers and Ondo-class oilers, because these oilers were not able to chase the aircraft carrier. In 1929, the IJN decided their combat ship (battleship, aircraft carrier, cruiser, destroyer, submarine and torpedo boat) fuel only to heavy crude oil. And, the IJN was paid a grant to newly build large/high-speed tankers. In 1931, two marine transportation companies built the tankers which the IJN wanted. One was the 9,900 tons/17.5 knot Teiyō Maru, the other the 9,500 tons/18.8 knots Fujisan Maru. The IJN was satisfied by Fujisan Maru. The IJN recommended building of the improved Fujisan Maru class tanker.

Construction In 1932, the ordered two tankers Tōa Maru and Kyokutō Maru from the Kawasaki Shipbuilding Corporation. In total 17 tankers were built with the same basic drawings, until 1943. All sisters participated in World War II. However, they were not able to survive at all.

Ships in classes

Tōa Maru class This is the first production model of the Kawasaki-type tankers. Their success gave courage to other steamship companies. Subsidy # Name Builder Laid down Launched Completed Owner 13 Kawasaki, Kōbe Shipyard 24 April 1933 2 April 1934 23 June 1934 Iino Lines 18 Kyokutō Maru renamed Kanji name to on 5 July 1938. Kawasaki, Kōbe Shipyard 25 November 1933 11 October 1934 15 December 1934 Iino Lines

Tatekawa Maru class The second production model. They were built according to the same Tōa Maru class drawings. However, their details were different by the steamship company which they placed an order with (example: Nippon Maru removed one dry cargo hold). Narrow sense of the Kawasaki-type tanker was until the Kyūei Maru. Kyūei Maru was equipped for surplus stocks of the Argentina Maru machinery. Subsidy # Name Builder Laid down Launched Completed Owner Kawasaki, Kōbe Shipyard 20 October 1934 20 April 1935 30 June 1935 Kawasaki Line Kawasaki, Kōbe Shipyard 18 October 1935 24 April 1936 30 June 1936 Yamashita Line Kawasaki, Kōbe Shipyard 1 May 1936 31 October 1936 24 December 1936 Iino Lines 101 Kawasaki, Kōbe Shipyard 21 April 1937 4 September 1937 20 December 1937 Nippon Suisan 102 Kawasaki, Kōbe Shipyard 12 June 1937 30 December 1937 28 April 1938 Asano Bussan 104 Kawasaki, Kōbe Shipyard 4 September 1937 15 April 1938 30 June 1938 Nittō Mining Kawasaki, Kōbe Shipyard 15 April 1938 24 October 1938 21 February 1939 Nittō Mining 106 Kawasaki, Kōbe Shipyard 17 June 1938 26 December 1938 16 May 1939 Kokuyō Line Kawasaki, Kōbe Shipyard 29 June 1938 6 April 1939 28 October 1939 Kokuyō Line 107 Kawasaki, Kōbe Shipyard 25 October 1938 13 December 1939 28 February 1940 Kōbe Pier Kawasaki, Kōbe Shipyard 20 November 1942 3 June 1943 6 September 1943 Nittō Mining

Nisshō Maru class One of the variants of the Kawasaki-type tankers. Mitsubishi used many curves to reduce her air friction strength. Subsidy # Name Builder Laid down Launched Completed Owner 103 Mitsubishi, Yokohama Shipyard 10 August 1937 13 June 1938 29 November 1938 Shōwa Shipping

Kuroshio Maru class One of the variants of the Kawasaki-type tankers. Kuroshio Maru was equipped with a La-Mont boiler. Her design was used for the Type 1TL wartime standard ship. Subsidy # Name Builder Laid down Launched Completed Owner 105 Harima Zōsen, Aioi Factory 21 January 1938 8 December 1938 28 February 1939 Chūgai Line

Akatsuki Maru class One of the variants of the Kawasaki-type tankers. The Harima Zōsen used the Sulzer diesel. Subsidy # Name Builder Laid down Launched Completed Owner 108 Harima Zōsen, Aioi Factory 21 June 1937 20 August 1938 31 October 1938 Japan Line Harima Zōsen, Aioi Factory 25 January 1938 10 June 1939 15 August 1939 Japan Line

Service Name Career (extract), fateDateContents Tōa Maru 1934–1941 Sailed for the import oil into Japan (67 times). 1 September 1941 Enlisted by the IJN. On 20 September, classified to auxiliary oiler. 1 December 1941 Assigned to the 6th Fleet. 5 April 1942 Assigned to the Combined Fleet. 21 May 1942 Entry to the 1st Fleet. 25 November 1943 Sunk by USS Searaven at north of Pohnpei . 5 January 1944 Removed from naval ship lists, and discharged. Kyokutō Maru 1934–1938 Sailed for the import oil into Japan (35 times). 1 July 1938 Enlisted by the IJN. On 7 July, classified to auxiliary fleet oiler, and assigned to the Combined Fleet. 18 November 1941 Entry to the 1st Air Fleet. 15 January 1942 Renamed Ōyashima Maru.In the IJN official document, Ōyashima Maru appears once. However, their later official document used Kyokutō Maru. 5 May 1944 Assigned to the 1st Mobile Fleet. 1 August 1944 Assigned to the Combined Fleet. 6 September 1944 Entry to the Kamoi Convoy (Singapore-Manila). On 20 September, arrived at Manila. 21 September 1944 Heavy damaged by aircraft at Manila Bay, later sunk in shallow water. 10 March 1945 Removed from naval ship lists, and discharged. 1951 Salvaged and sold to Nihon Tanker. 5 September 1952 Repairs were completed, and renamed California Maru. 21 July 1964 Retired. Tatekawa Maru 1935–1941 Sailed for the import oil into Japan, many times. 20 December 1941 Enlisted by the IJN. 1 September 1943 Classified to auxiliary oiler, and assigned to the Ministry of the Navy. 9 May 1944 Assigned to the 1st Mobile Fleet. 24 May 1944 Sunk by USS Gurnard at east of Mindanao . 10 July 1944 Removed from naval ship lists. On 20 July, discharged. Nippon Maru 1936–1941 Sailed for the import oil into Japan, many times. 7 September 1941 Enlisted by the IJN. On 20 September, classified to auxiliary oiler, and assigned to the Combined Fleet. 18 November 1941 Entry to the 1st Air Fleet. 12 May 1943 Entry to the Northeast Area Fleet. 14 January 1944 Sunk by USS Scamp at southwest of Woleai . 10 March 1944 Removed from naval ship lists, and discharged. Tōhō Maru 1936–1941 Sailed for the import oil into Japan (51 times). 20 August 1941 Enlisted by the IJN. On 20 September, classified to auxiliary oiler, and assigned to the Combined Fleet. 26 November 1941 Entry to the 1st Air Fleet. 27 May 1942 Entry to the 4th Carrier Division. 29 March 1943 Sunk by USS Gudgeon at east-northeast of Samarinda . 1 May 1943 Removed from naval ship lists, and discharged. Itsukushima Maru 1937–1941 Accompanied to fleet of whalers. 22 November 1941 Enlisted by the IJN. 1 September 1943 Classified to auxiliary oiler, and assigned to the Ministry of the Navy. 9 May 1944 Assigned to the 1st Mobile Fleet. 20 September 1944 Assigned to the Combined Fleet. 20 September 1944 Entry to the 2nd Fleet. 27 October 1944 Heavy damaged by USS Bergall at southwest of Balambangan Island . On 31 October, sunk. 10 December 1944 Removed from naval ship lists, and discharged. Gen'yō Maru 1938–1941 Sailed for the import oil into Japan, many times. 2 November 1941 Enlisted by the IJN. On 10 December, classified to auxiliary oiler, and assigned to the 3rd Fleet. 10 March 1942 Assigned to the 2nd Southern Expeditionary Fleet. 25 August 1942 Assigned to the Combined Fleet. 5 May 1944 Assigned to the 1st Mobile Fleet. 20 June 1944 Sunk during the Battle of the Philippine Sea at north-northwest of Palau . 10 August 1944 Removed from naval ship lists, and discharged. Nichiei Maru 1938–1941 Sailed for the import oil into Japan, many times. 31 October 1941 Enlisted by the IJN. On 10 November, classified to auxiliary oiler, and assigned to the Combined Fleet. August 1942 Assigned to the Southeast Area Fleet. 25 December 1943 Assigned to the Combined Fleet. 5 May 1944 Assigned to the 1st Mobile Fleet. 23 July 1944 Assigned to the Combined Fleet. 16 October 1944 Assigned to the 2nd Fleet. 3 January 1945 Heavy damaged by USS Besugo at north of Kuantan. On 7 January, sunk at . 10 March 1945 Removed from naval ship lists, and discharged. Tōei Maru 1939–1940 Sailed for the import oil into Japan, several times. 23 December 1940 Enlisted by the IJN. On 26 December, classified to auxiliary oiler. 1 July 1941 Classified to auxiliary fleet oiler. 15 October 1941 Classified to auxiliary oiler, and assigned to the Combined Fleet. 18 November 1941 Entry to the 1st Air Fleet. 18 January 1943 Sunk by USS Silversides off Truk . 1 April 1943 Removed from naval ship lists, and discharged. Kokuyō Maru 1939–1940 Sailed for the import oil into Japan, several times. 16 November 1940 Enlisted by the IJN. On 26 December, classified to auxiliary oiler. 15 June 1941 Classified to auxiliary fleet oiler. 15 October 1941 Classified to auxiliary oiler, and assigned to the Combined Fleet. 18 November 1941 Entry to the 1st Air Fleet. 5 May 1944 Assigned to the 1st Mobile Fleet. 30 July 1944 Sunk by USS Bonefish at east of Sandakan . 10 September 1944 Removed from naval ship lists, and discharged. Ken'yō Maru 1939–1941 Sailed for the import oil into Japan, several times. 17 August 1941 Enlisted by the IJN. On 5 September, classified to auxiliary oiler, and assigned to the Combined Fleet. 18 November 1941 Entry to the 1st Air Fleet. 10 August 1942 Entry to the 3rd Fleet. 14 January 1944 Sunk by USS Guardfish at southeast of Yap . 10 March 1944 Removed from naval ship lists, and discharged. Shinkoku Maru 1940–1941 Sailed for the import oil into Japan, several times. 18 August 1941 Enlisted by the IJN. On 5 September, classified to auxiliary oiler, and assigned to the Combined Fleet. 18 November 1941 Entry to the 1st Air Fleet. 17 February 1944 Sunk during the Operation Hailstone. 31 March 1944 Removed from naval ship lists, and discharged. Kyūei Maru 15 October 1943 Enlisted by the IJN. Classified to auxiliary oiler, and assigned to the Yokosuka Naval District. 25 October 1943 Assigned to the Ministry of the Navy. 21 December 1943 Entry to the Hi-27 Convoy. 27 December 1943 Sunk by USS Flying Fish at southeast of Kaohsiung . 5 February 1944 Removed from naval ship lists, and discharged. Nisshō Maru 1938–1941 Sailed for the import oil into Japan, many times. 23 February 1942 Enlisted by the IJN. On 25 February, classified to auxiliary oiler. 1 July 1942 Assigned to the Combined Fleet. 25 February 1944 Sunk by USS Hoe at Bohol Sea . 31 March 1944 Removed from naval ship lists, and discharged. Kuroshio Maru 1939–1941 Sailed for the import oil into Japan, many times. 15 August 1941 Enlisted by the IJN. On 5 September, classified to auxiliary oiler. 10 January 1942 Assigned to the Ministry of the Navy. 20 March 1942 Removed from naval ship lists, and discharged. September 1942 Allotted to the Imperial Japanese Army. 31 December 1944 Entry to the Hi-87 Convoy. 21 January 1945 Sunk by aircraft at Kaohsiung. Akatsuki Maru 1938–1941 Sailed for the import oil into Japan, many times. 17 November 1941 Enlisted by the Navy.Akatsuki Maru was not registered to naval ship list. 29 May 1943 Sunk by USS Saury at northwest of Naha . 30 June 1943 Discharged. Akebono Maru 1939–1941 Sailed for the import oil into Japan, many times. 1 December 1941 Enlisted by the IJN. On 7 December, classified to auxiliary oiler. 10 January 1942 Assigned to the Combined Fleet. 30 March 1944 Entry to the PaTa-07 Convoy. 31 March 1944 Heavy damaged by aircraft at Palau. Later scuttled. 10 May 1944 Removed from naval ship lists, and discharged.

Characteristics