Class overview
Kyokutō Maru (left), Kokuyō Maru, Nippon Maru and Shinkoku Maru (right) on 1 December 1941
Name	Kawasaki-type oilers Tōa Maru class Tatekawa Maru class Nisshō Maru class Kuroshio Maru class Akatsuki Maru class
Builders	Kawasaki Shipbuilding Corporation Harima Zōsen Corporation Mitsubishi Heavy Industries
Operators	Asano Bussan Chūgai Line Iino Lines Japan Line Kawasaki Line Kōbe Pier Kokuyō Line Mitsu Line Nippon Suisan Nittō Mining Nihon Tanker Yamashita Line Imperial Japanese Navy Imperial Japanese Army
Preceded by	Fujisan Maru
Succeeded by	Type 1TL wartime standard ship
Cost	Tōa Maru: 2,600,000 JPY
Built	1933 – 1943
In commission	1934 – 1964
Planned	17
Completed	17
Lost	17
Retired	(1)
General characteristics
Type	Oiler
Displacement	approx. 10,000 long tons (10,160 t)
Length	around 152 m (498 ft 8 in) Lpp
Beam	around 20.0 m (65 ft 7 in)
Draught	around 11.4 m (37 ft 5 in)
Propulsion	1 × diesel, single shaft, around 10,000 bhp or boiler and turbine
Speed	around 20 knots (23 mph; 37 km/h)
Armament	(example) Shinkoku Maru, 1941 2 × 150 mm (5.9 in) naval guns 2 × 76.2 mm (3.00 in) AA guns 2 × 7.7 mm machine guns Gen'yo Maru, 1941 2 × 76.2 mm (3.00 in) AA guns 2 × Type 96 25 mm AA guns Itsukushima Maru, 1944 1 × 120 mm (4.7 in) naval gun 16 × Type 96 25 mm AA guns 18 × depth charges 1 × Type 93 hydrophone Kyokutō Maru, 1944 2 × 120 mm (4.7 in) AA guns 16 × Type 96 25 mm AA guns Nichiei Maru, 1944 2 × 120 mm (4.7 in) AA guns 16 × Type 96 25 mm AA guns 12 × depth charges 1 × Type 93 hydrophone

The Kawasaki-type oiler (川崎型油槽船,, Kawasaki-gata Yusōsen) was a type of oiler from Japan, serving during the 1930s and World War II. They do not have an official class name.^[1] 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 Iino Kaiun Kaisha (飯野海運,, Iino Lines) ordered two tankers Tōa Maru and Kyokutō Maru to the Kawasaki Shipbuilding Corporation. In total 17 tankers were built with the same basic drawings, until 1943.
All sisters participated to 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	Tōa Maru (東亜丸)	Kawasaki, Kōbe Shipyard	24 April 1933	2 April 1934	23 June 1934	Iino Lines
18	Kyokutō Maru (極東丸, 旭東丸) ^[2]	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
	Tatekawa Maru (建川丸)	Kawasaki, Kōbe Shipyard	20 October 1934	20 April 1935	30 June 1935	Kawasaki Line
	Nippon Maru (日本丸)	Kawasaki, Kōbe Shipyard	18 October 1935	24 April 1936	30 June 1936	Yamashita Line
	Tōhō Maru (東邦丸)	Kawasaki, Kōbe Shipyard	1 May 1936	31 October 1936	24 December 1936	Iino Lines
101	Itsukushima Maru (厳島丸)	Kawasaki, Kōbe Shipyard	21 April 1937	4 September 1937	20 December 1937	Nippon Suisan
102	Gen'yō Maru (玄洋丸)	Kawasaki, Kōbe Shipyard	12 June 1937	30 December 1937	28 April 1938	Asano Bussan
104	Nichiei Maru (日栄丸)	Kawasaki, Kōbe Shipyard	4 September 1937	15 April 1938	30 June 1938	Nittō Mining
	Tōei Maru (東栄丸)	Kawasaki, Kōbe Shipyard	15 April 1938	24 October 1938	21 February 1939	Nittō Mining
106	Kokuyō Maru (国洋丸)	Kawasaki, Kōbe Shipyard	17 June 1938	26 December 1938	16 May 1939	Kokuyō Line
	Ken'yō Maru (健洋丸)	Kawasaki, Kōbe Shipyard	29 June 1938	6 April 1939	28 October 1939	Kokuyō Line
107	Shinkoku Maru (神国丸)	Kawasaki, Kōbe Shipyard	25 October 1938	13 December 1939	28 February 1940	Kōbe Pier
	Kyūei Maru (久栄丸)	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	Nisshō Maru (日章丸)	Misubishi, 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	Kuroshio Maru (黒潮丸)	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	Akatsuki Maru (あかつき丸)	Harima Zōsen, Aioi Factory	21 June 1937	20 August 1938	31 October 1938	Japan Line
	Akebono Maru (あけぼの丸)	Harima Zōsen, Aioi Factory	25 January 1938	10 June 1939	15 August 1939	Japan Line

Service

Name	Career (extract), fate
Name	Date	Contents

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 08°30′N 158°00′E / 8.500°N 158.000°E / 8.500; 158.000.
	5 January 1944	Removed from naval ship lists, and discharged.

Kyokutō Maru Ōyashima Maru (大八州丸) California Maru (かりほるにあ丸)	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.^[3]
	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 05°45′N 125°43′E / 5.750°N 125.717°E / 5.750; 125.717.
	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 05°02′N 140°03′E / 5.033°N 140.050°E / 5.033; 140.050.
	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 00°00′N 118°18′E / 0.000°N 118.300°E / 0.000; 118.300.
	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 07°17′N 116°45′E / 7.283°N 116.750°E / 7.283; 116.750. 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 15°35′N 133°30′E / 15.583°N 133.500°E / 15.583; 133.500.
	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 06°45′N 102°55′E / 6.750°N 102.917°E / 6.750; 102.917.
	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 06°19′N 150°15′E / 6.317°N 150.250°E / 6.317; 150.250.
	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 06°07′N 120°00′E / 6.117°N 120.000°E / 6.117; 120.000.
	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 05°23′N 141°32′E / 5.383°N 141.533°E / 5.383; 141.533.
	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 21°25′N 118°05′E / 21.417°N 118.083°E / 21.417; 118.083.
	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 05°50′N 126°00′E / 5.833°N 126.000°E / 5.833; 126.000.
	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.^[4]
	29 May 1943	Sunk by USS Saury at northwest of Naha 27°40′N 125°55′E / 27.667°N 125.917°E / 27.667; 125.917.
	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

Name	Displacement (gross)	Length	Beam	Draught	Propulsion	Speed	Capacity
Tōa Maru	10,052 long tons (10,213 t)	160.2 m (525 ft 7 in) overall 152.4 m (500 ft 0 in) Lpp	19.8 m (65 ft 0 in)	11.2 m (36 ft 9 in)	1 × MAN/Kawasaki D8Z-70/120 diesel single shaft, 8,911 bhp	18.4 knots (21.2 mph; 34.1 km/h)	16,093 cubic meters oil^[5] 4 passengers^[5]
Kyokutō Maru (Ōyashima Maru)	10,051 long tons (10,212 t)	160.2 m (525 ft 7 in) overall 152.4 m (500 ft 0 in) Lpp	19.8 m (65 ft 0 in)	11.3 m (37 ft 1 in)	1 × MAN/Kawasaki D8Z-70/120 diesel single shaft, 8,963 bhp	18.9 knots (21.7 mph; 35.0 km/h)	16,100 cubic meters oil 8 passengers
Tatekawa Maru	10,091 long tons (10,253 t)	160.2 m (525 ft 7 in) overall 152.4 m (500 ft 0 in) Lpp	19.8 m (65 ft 0 in)	11.3 m (37 ft 1 in)	1 × MAN/Kawasaki D8Z-70/120 diesel single shaft, 10,658 bhp	19.9 knots (22.9 mph; 36.9 km/h)
Nippon Maru	9,971 long tons (10,131 t)	160.2 m (525 ft 7 in) overall 152.4 m (500 ft 0 in) Lpp	19.8 m (65 ft 0 in)	11.3 m (37 ft 1 in)	1 × MAN/Kawasaki D8Z-70/120 diesel single shaft, 9,773 bhp	19.2 knots (22.1 mph; 35.6 km/h)	14,590 cubic meters oil^[6] 6 passengers^[7]
Tōhō Maru	9,997 long tons (10,157 t)	160.2 m (525 ft 7 in) overall 152.4 m (500 ft 0 in) Lpp	19.8 m (65 ft 0 in)	11.3 m (37 ft 1 in)	1 × MAN/Kawasaki D8Z-70/120 diesel single shaft, 9,903 bhp	20.1 knots (23.1 mph; 37.2 km/h)
Itsukushima Maru	10,007 long tons (10,168 t)	160.2 m (525 ft 7 in) overall 152.4 m (500 ft 0 in) Lpp	19.8 m (65 ft 0 in)	11.3 m (37 ft 1 in)	1 × MAN/Kawasaki D8Z-70/120 diesel single shaft, 11,693 bhp	19.8 knots (22.8 mph; 36.7 km/h)
Gen'yō Maru	10,018 long tons (10,179 t)	160.2 m (525 ft 7 in) overall 152.4 m (500 ft 0 in) Lpp	19.8 m (65 ft 0 in)	11.3 m (37 ft 1 in)	1 × MAN/Kawasaki D8Z-70/120 diesel single shaft, 11,100 bhp	19.7 knots (22.7 mph; 36.5 km/h)
Nichiei Maru	10,020 long tons (10,181 t)	160.2 m (525 ft 7 in) overall 152.4 m (500 ft 0 in) Lpp	19.8 m (65 ft 0 in)	11.3 m (37 ft 1 in)	1 × MAN/Kawasaki D8Z-70/120 diesel single shaft, 11,570 bhp	20.0 knots (23.0 mph; 37.0 km/h)
Tōei Maru	10,022 long tons (10,183 t)	160.2 m (525 ft 7 in) overall 152.4 m (500 ft 0 in) Lpp	19.8 m (65 ft 0 in)	11.3 m (37 ft 1 in)	1 × MAN/Kawasaki D8Z-70/120 diesel single shaft, 11,210 bhp	19.4 knots (22.3 mph; 35.9 km/h)
Kokuyō Maru	10,026 long tons (10,187 t)	160.2 m (525 ft 7 in) overall 152.4 m (500 ft 0 in) Lpp	19.8 m (65 ft 0 in)	11.3 m (37 ft 1 in)	1 × MAN/Kawasaki D8Z-70/120 diesel single shaft, 11,033 bhp	19.6 knots (22.6 mph; 36.3 km/h)
Ken'yō Maru	10,024 long tons (10,185 t)	160.2 m (525 ft 7 in) overall 152.4 m (500 ft 0 in) Lpp	19.8 m (65 ft 0 in)	11.3 m (37 ft 1 in)	1 × MAN/Kawasaki D8Z-70/120 diesel single shaft, 11,380 bhp	20.2 knots (23.2 mph; 37.4 km/h)
Shinkoku Maru	10,020 long tons (10,181 t)	160.2 m (525 ft 7 in) overall 152.4 m (500 ft 0 in) Lpp	19.8 m (65 ft 0 in)	11.3 m (37 ft 1 in)	1 × MAN/Kawasaki D8Z-70/120 diesel single shaft, 11,565 bhp	19.8 knots (22.8 mph; 36.7 km/h)
Kyūei Maru	10,171 long tons (10,334 t)	160.2 m (525 ft 7 in) overall 152.4 m (500 ft 0 in) Lpp	19.8 m (65 ft 0 in)	11.3 m (37 ft 1 in)	1 × Mitsubishi MS11-72/125 diesel single shaft, 7,360 bhp
Nisshō Maru	10,526 long tons (10,695 t)	159.0 m (521 ft 8 in) Lpp	20.0 m (65 ft 7 in)	12.0 m (39 ft 4 in)	1 × MAN/Mitsubishi D8Zu-72/120P diesel single shaft, 9,400 bhp	19.6 knots (22.6 mph; 36.3 km/h)
Kuroshio Maru	10,384 long tons (10,551 t)	153.8 m (504 ft 7 in) Lpp	20.1 m (65 ft 11 in)	11.4 m (37 ft 5 in)	3 × La-Mont/Kawasaki high-pressure boiler Ishikawajima turbine, single shaft, 11,805 shp	20.7 knots (23.8 mph; 38.3 km/h)
Akatsuki Maru	10,216 long tons (10,380 t)	160.2 m (525 ft 7 in) overall 152.4 m (500 ft 0 in) Lpp	19.81 m (65 ft 0 in)	11.43 m (37 ft 6 in)	1 × Sulzer/Kōbe diesel single shaft, 10,678 bhp	20.13 knots (23.17 mph; 37.28 km/h)
Akebono Maru	10,182 long tons (10,345 t)	160.2 m (525 ft 7 in) overall 152.4 m (500 ft 0 in) Lpp	19.81 m (65 ft 0 in)	11.43 m (37 ft 6 in)	1 × Sulzer/Kōbe diesel single shaft, 10,820 bhp	20.063 knots (23.088 mph; 37.157 km/h)