TOKUSETSU UNSOSEN ZATSUYOSEN!

Stories and Battle Histories of the IJN's Auxiliary Transport Fleet

22 January 2017

By Gilbert Casse, Bob Hackett and Peter Cundall

Discussion & Questions


(Auxiliary transport BRASIL MARU in wartime by Ueda Kihachiro)


Prior to and during the Pacific War, the Imperial Japanese Navy enlisted some of Japan's merchant fleet's former cargo ships, passenger-cargo and liners. They were converted to military use and became Tokusetsu Unsosen Zatsuyosen (Converted Auxiliary Transports) used to transport troops, military equipment including tanks, weapons, munitions, crated aircraft, parts and stores. Many were also given other wartime roles.

Between 1937 and 1945, 223 Zatsuyosen were employed by the IJN. Several ships were either removed or transferred to other categories before the outbreak of the Pacific War. During the war, 65 ships from other categories were rerated as Zatsuyosen. Other ships were also requisitioned by the IJN, but not enlisted. They were called Ippan Choyosen (General Requisitioned Ships) and manned by civilian crews. The IJA and the civilian shipping administration requisitioned many other ships.

To summarize, during the war employment of ex-merchant ships was divided into three main administrative categories:
A = requisitioned and operated by the Japanese Army and called Rikugun Yusosen (IJA Transports). They include cargo, passenger-cargo, liners and tankers.
B = requisitioned and operated by the Japanese Navy with civilian crew (captain often being Navy Reserve). These are called Ippan Choyosen.
C = controlled and operated by the Senpaku UnŽeikai (Civilian Shipping Administration)
X = requisitioned by the IJN and converted into armed Naval Auxiliaries with IJN crews (gunboats, minesweepers, etc.) and named Tokusetsu Kansen followed by another suffix for the ship’s use.

Beside the above categories, there were many shared employments Army/Civilian (A/C) and Navy/Civilian (B/C). These ships were called Haitosen. Normally, this meant that the vessel on its outbound journey was under Army or Navy control carrying troops, military supplies, etc., and on its return voyage was carrying cargo for the benefit of the civilian owner(s) of ship.

While used by the Army, Haitosen also received Army transport numbers like Army requisitioned vessels (A). Employments by Army or Navy could also be expanded, meaning that the ship was used by Army/Navy for one full turn (outward and homeward voyage) or even a series of voyages.

This page will cover the activities of 223 auxiliary transports including 13 captured/raised former Allied ships. The 28 Axis (10 Vichy French, eight German, eight Italian and one Finnish) vessels in Japanese service have been covered in our SEMPAKU UNEIKAI SIYOSEN (Government Requisitioned Ships) page.

The Japanese found many and varied roles for their merchant fleet's ex-passenger-cargo ships. Twenty were converted in late 1942 to serve as emergency oil tankers (OHKYU YUSOSEN) and are covered on our extensive YUSOSEN! page. Fourteen such ships were converted for use as armed merchant cruisers and are covered on our TOKUSETSU JUNYOKAN! page, ten others became aircraft transports as covered on KOKUKI-UMPANSEN! Four transports were converted to destroyer tenders and are covered SUIRAI-BOKAN! Nine such ships also became seaplane tenders as detailed on TOKUSETSU SUIJOKI-BOKAN!.

Similarly, another eight transports were converted to submarine tenders and are covered on SENSUI-BOKAN!, ten others became ammunition suppy ships and are on KYUHEIKAN!, six were converted to hospital ships as covered on BYOINSEN, two acted as repair ships as detailed on KOSAKUKAN! and finally, one even became an escort carrier as covered on KIDO BUTAI.






Tabular Records of Movement (TROMs):
IJN Auxiliary Transports
(Classes link to specifications summaries)

NACHISAN MARU Class

Nachisan Maru (revised 1 December 2013)

SENKO MARU Class

Senko Maru (revised 11 December 2016)
Manko Maru (revised 22 January 2017)
NACHI MARU Class

Muro Maru (posted 7 February 2009)

MYOKO MARU Class

Myoko Maru (revised 7 March 2015)
Hakkai Maru (revised 30 April 2010)

KIMISHIMA MARU Class

Kimishima Maru (revised 11 December 2016)

TATSUWA MARU Class

Tatsuwa Maru (revised 8 December 2013)
Tatsuho Maru (posted 6 August 2011)
Tatsumiya Maru (posted 6 August 2011)
Tatsuharu Maru (posted 30 April 2010)

MUKO MARU Class

Muko Maru (revised 27 November 2016)
Naniwa Maru (revised 13 March 2015)



MEITEN MARU Class

Meiten Maru (revised 22 January 2017)
KAIHEI MARU Class

Kaihei Maru (posted 19 August 2011)
Kenryu Maru (revised 20 September 2015)
KOFUKU MARU Class

Kofuku Maru (posted 3 September 2011)
KENYO MARU Class

Kenyo Maru (revised 27 September 2015)

TOYO MARU Class

Kaisho Maru (revised 20 September 2015)
Mitakesan Maru (revised 20 September 2015)
Toyo Maru (revised 14 December 2012)
Kunishima Maru (revised 28 September 2014)
Toyo Maru No. 2 (revised 27 September 2015)
Shinyo Maru (revised 8 December 2013)

NAGARA MARU Class

Nojima Maru (revised 1 January 2016)
Noshiro Maru
(revised 20 November 2010)
GENKAI MARU
Class

Choko Maru (revised 13 September 2015)
Eiko Maru No. 2 Go(revised 24 July 2016)

KINAI MARU Class

Kinai Maru (revised 24 July 2016)
Hokuroku Maru (revised 24 July 2016)
Nankai Maru (revised 13 March 2015)
Hokkai Maru (revised 24 July 2016)
Tokai Maru (posted 22 October 2011)
Sanyo Maru (revised 6 March 2010)

HEITO MARU Class

Heito Maru (revised 29 October 2011)
Shoka Maru (revised 8 December 2013)
Taito Maru (revised 8 January 2013)

CUBA MARU Class

Cuba Maru (posted 5 November 2011)
MIFUNE MARU Class

Mikage Maru No. 3 (posted 5 November 2011)

OKITSU MARU Class

Okitsu Maru (revised 31 July 2016)

SHINKYO MARU Class

Shinkyo Maru (revised 7 May 2016)
Anshu Maru (revised 22 January 2017)
Seikyo Maru (posted 19 November 2011)
Nikkai Maru (posted 26 November2011)
Rakuto Maru (revised 13 March 2015)

SHOHEI MARU Class

Shohei Maru (revised 22 March 2015)

SHOAN MARU Class

Shoan Maru (posted 2 December 2011)
Meiyo Maru (updated 28 February 2014)
SHINKO MARU Class

Yamagiri Maru (revised 29 March 2015)
Keiyo Maru (revised 8 May 2010)

ASAHISAN MARU Class Class

Asahisan Maru(revised 21 September 2014)
Akashisan Maru (revised 30 April 2016)

KOMAKI MARU Class

Kano Maru (revised 30 April 2016)
KAIKO MARU Class

Kaiko Maru (revised 23 November 2013)

SEIA MARU Class

Nana Maru (revised 31 July 2016)
Toa Maru No. 2 Go (revised 27 April 2014)
KOTO MARU No. 2 GO Class

Koto Maru No. 2 Go (revised 16 August 2013)
Tamashima Maru (revised 2 June 2012)
Kosei Maru (revised 1 December 2013)

AZUMASAN MARU Class

Azumasan Maru (revised 22 January 2017)
Amagisan Maru (revised 24 July 2016)
CHOWA MARU Class

Chowa Maru (revised 23 November 2013)

Nikkoku Maru (posted 7 April 2012)
Nittei Maru (revised 7 May 2016)
Chuwa Maru (posted 5 May 2012)

HAKUBASAN MARU Class

Hakonesan Maru (posted 5 May 2012)

SHOKEI MARU Class

Shokei Maru (revised 22 March 2015)
Nichiei Maru(posted 2 June 2012)

KOSEI MARU Class

Kosei Maru (revised 1 December 2013)

KOGANE MARU Class

Shirogane Maru (posted 7 July 2012)

KINSEN MARU Class

Kinsen Maru (posted 7 July 2012)

KINJOSAN MARU Class

Kimposan Maru (posted 7 July 2012)
PEACETIME STANDARD TYPE (D) Class

Tairyu Maru (posted 4 August 2012)
Nankai Maru
No. 2
(revised 27 November 2016)
Hirotama Maru (posted 1 September 2012)
Tatsutagawa Maru(revised 27 September 2015)
Seizan Maru
No. 2
(revised 11 May 2014)
Shoko Maru (revised 7 May 2016)
Katori Maru (posted 6 October 2012)
Kizugawa Maru (revised 20 September 2015)

SHUNKO MARU Class

Kirikawa Maru (revised 20 September 2015)
Kikukawa Maru (revised 7 March 2015)
Hiyoshi Maru
(revised 1 March 2015)

KACHOSAN MARU Class

Kasagisan Maru (posted 1 December 2012)
HOKUYO MARU Class

Hokusho Maru (revised 13 September 2015)

IKUTA MARU Class

Nagata Maru (posted 1 December 2012)
Yamadori Maru (revised 20 April 2014)

SANTO MARU Class

Santo Maru
(revised 27 September 2015)
Sansei Maru (revised 13 March 2015)

MIKAGE MARU No. 18 Class

Hino Maru No. 3(revised 21 September 2014)



TOEI MARU Class

Toei Maru (revised 6 August 2016)

TENRYU MARU Class

Tenryu Maru (revised 22 March 2015)

Shinryu Maru (revised 8 December 2013)

KOTO MARU Class

Koto Maru (revised 1 December 2013)
NAGISAN MARU Class

Nagisan Maru
(revised 31 July 2016)
Nasusan Maru (posted 8 April 2012)

TARUSHIMA MARU Class

Tarushima Maru (revised 22 March 2015)
Yamafuku Maru (revised 14 May 2016)

KOKAI MARU Class

Kokai Maru (revised 28 September 2014)



SHOKO MARU Class

Shoko Maru (posted 1 June 2013)

KINUGASA MARU Class

Kinugasa Maru (posted 17 July 2005)
Kagu Maru (revised 21 September 2014)

UNYO MARU No. 2 Class

Unyo Maru No. 2
(Posted 1 June 2013)
KOSHIN MARU Class

Koshin Maru (posted 1 September 2012)

TONAN MARU No. 2 Class

Tonan Maru No. 2 (posted 30 April 2010)
Tonan Maru No. 3 (revised 17 April 2010)

AKIURA MARU Class

Kozui Maru (posted 24 September 2011)
Fujikawa Maru (revised 8 May 2010)
LIMA MARU Class

Lyons Maru (revised 8 May 2010)
Matsumoto Maru (posted 6 August 2011)



KIRISHIMA MARU Class

Kirishima Maru (revised 30 April 2010)

KAMIKAWA MARU Class

Kimikawa Maru (revised 12 December 2009)
Kunikawa Maru (revised 2 September 2009)
SHOUN MARU Class

Shoun Maru (posted 6/1/2013)

GOSHU MARU Class

Goshu Maru (revised 11 June 2011)
Goyo Maru (revised 8 May 2010)
KOSHIN MARU Class

Koshin Maru
(posted 1 July 2013)
Kogyo Maru (posted 24 July 2010)
Hitachi Maru (posted 25 October 2008)

PEACETIME STANDARD TYPE (C) Class

Imizu Maru
(revised 20 April 2014)

Wayo Maru
(posted 1 July 2013)
Ryuko Maru
(posted 1 August 2013)
Kanayamasan Maru (revised 20 April 2014)
AKAGISAN MARU Class

Akibasan Maru (revised 13 September 2015)
KASUGA MARU Class

Ikushima Maru (revised 22 January 2017)
Kasuga Maru No. 2 Go(posted 1 September 2013)
Shinkoku Maru (revised 31 July 2016)



MIKAGE MARU No. 20 Class

Hino Maru No. 5 (revised 27 November 2016)
Shinsei Maru No. 18
(revised 31 July 2016)

KANSAI MARU Class

Kanto Maru (posted 26 October 2007)
OGASHIMA MARU Class

Ogashima Maru (posted 1 October 2013)

TAIJUN MARU Class

Taijun Maru (posted 1 October 2013)

CANBERRA MARU
Class

Tokyo Maru (posted 11 January 2013)

SANTOS MARU Class

Santos Maru (revised 13 March 2010)
Montevideo Maru (posted 1 November 2013)

KOGANE MARU Class

Kogane Maru (posted 12 January 2013)
ARATAMA MARU Class

Yamashimo Maru
(revised 14 May 2016)



TENZAN MARU Class

Tenzan Maru (revised 31 July 2016)
Senzan Maru (revised 31 July 2016)

KENSHO MARU Class

Kensho Maru
(revised 20 September 2015)

KIYOSUMI MARU Class

Kiyosumi Maru (revised 20 August 2010)

HAKONE MARU Class

Hakusan Maru (revised 30 April 2016)
Hakozaki Maru (revised 22 January 2017)
KEISHO MARU Class

Keisho Maru (posted 1 January 2014)

BRITISH WW1
STD C TYPE
Class

Shoei Maru (posted 1 February 2014)

TOYOSAKA MARU Class

Toyosaka Maru (posted 1 February 2014)

Shinyo Maru No. 8(posted 1 February 2014)

Nissho Maru No. 18
(posted 1 March 2014)

HAKUTETSU MARU No. 7 Class

Hakutetsu Maru No. 7
(posted 1 March 2014)


HAKUTETSU MARU No. 11 Class

Hakutetsu Maru No. 15
(posted 1 March 2014)



HIDE MARU Class

Hide Maru (posted 21 August 2010)

AZUMA MARU Class

Azuma Maru (revised 28 February 2014)
KEISHIN MARU Class

Yoshinogawa Maru
(posted 1 April 2014)

ARGENTINA MARU Class

Argentina Maru (revised 13 September 2015)
Brasil Maru
(posted 1 April 2014)
PEACETIME
STANDARD
TYPE 1E Class

Nissei Maru
(posted 1 April 2014)

SHOEI MARU Class

Fukuyama Maru
(revised 21 September 2014)

NICHIYU MARU Class

Nichiyu Maru
(revised 7 May 2015



SUWA MARU Class

Suwa Maru
(revised 18 May 2014)
SEIZAN MARU Class

Seizan Maru
(posted 1 June 2014)

RYOTOKU MARU Class

Ryotoku Maru
(posted 1 June 2014)
KAZAN MARU Class

Tozan Maru
(posted 1 June 2014)

YOKO MARU Class

Yoko Maru (revised 14 May 2016)

SHOEI MARU Class

Shoei Maru (revised 7 May 2016)

Shoho Maru (posted 1 August 2014)

HYAKUFUKU MARU Class

Hyakufuku Maru
(posted 1 September 2014)
TOSHO MARU Class

Tosho Maru
(posted 1 September 2014)
Daigen Maru No. 7
(posted 1 September 2014)
UNKAI MARU No. 10 MARU Class

Unkai Maru No. 10
(posted 1 October 2014)
BUENOS AIRES MARU Class

Rio de Janeiro Maru (revised 2 July 2011)

HIKAWA MARU Class

Hie Maru(revised 13 March 2010)
AKAGI MARU Class

Asaka Maru (revised 20 February 2010)

Awata Maru (revised 20 November 2010)
HOKOKU MARU Class

Aikoku Maru (revised 1 September 2014)
Gokoku Maru (revised 1 September 2014)

FUKUEI MARU No. 10 Class

Fukuei Maru No. 10(revised 22 January 2017)
HINO MARU No. 2 Class

Hino Maru No. 2 (revised 30 April 2016)



KOWA MARU Class

Kowa Maru (revised 7 May 2016)

CHOJO MARU Class

Choan Maru No. 2 Go (revised 13 September 2015)
Choko Maru No. 2 Go (posted 1 November 2014)
HIROTA MARU Class

Hirota Maru (posted 1 December 2014)
Yoshida Maru (revised 14 May 2016)
HIYOSHI MARU No. 2 GO Class

Hiyoshi Maru No. 2 Go (posted 1 December 2014)
FUKKEN MARU Class

Busho Maru (posted 1 February 2015)

NISSHO MARU No. 2 Class

Nissho Maru No. 2 (posted 1 February 2015)

NISSHO MARU No. 16 Class

Nissho Maru No. 16 (posted 1 February 2015)
JUZAN MARU Class

Juzan Maru (posted 1 March 2015)



IWATO MARU Class

Iwato Maru (posted 1 March 2015)

TOYO MARU No. 3 Class

Toyo Maru No. 3 (revised 6 August 2016)
NISSHO MARU No. 5 Class

Nissho Maru No. 5 (posted 4 April 2015)

NIPPONKAI MARU Class

Nipponkai Maru (revised 12 June 2010)
ASAHI MARU Class

Asahi Maru (posted 20 August 2005)

KAMITSU MARU Class

Kunitsu Maru (posted 4 April 2015)

OTORI MARU Class

Otori Maru (posted 4 April 2015)

HIKOSHIMA MARU Class

Hikoshima Maru (posted 2 May 2015)
SEIGA MARU Class

Kaika Maru (posted 2 May 2015)

DAICHO MARU Class

Daicho Maru (posted 2 May 2015)
CHOI MARU Class

Choi Maru (posted 4 July 2015)

KIBI MARU Class

Meisho Maru (posted 4 July 2015)

NAGOYA MARU Class

Nagoya Maru (revised 13 March 2010)

KIRI MARU No. 8 Class

Kiri Maru No. 8(posted 4 July 2015)
Shinko Maru No. 1 Go(posted 2 August 2015)



SHOSEI MARU Class

Shosei Maru (posted 2 August 2015)

KYUSHU MARU Class

Kyushu Maru
(posted 1 September 2015)
YAYOI MARU Class

Yayoi Maru (posted 1 September 2015)

KATSUYAMA MARU Class

Matsuyama Maru (posted 1 September 2015)


Captured Vessels in Japanese Service as Auxiliary Transports
(Ex-Countries link to specifications summaries)

Ex-American Vessels

Paran Maru (ex-Palawan)
(posted 2 October 2015)
Hokuhi Maru (ex-Cetus)
(posted 2 October 2015)
Anan Maru (ex-Anakan)
(posted 2 October 2015)

Ex-British Vessels

Nichirin Maru (ex-Mata Hari)
(posted 2 November 2015)
Hoki Maru (ex-Hauraki)
(revised 30 April 2016)
Kembu Maru (ex-Empire Blossom)
(posted 2 November 2015)
Keishu Maru (ex-Henry Keswick)
(posted 2 December 2015)
Risui Maru (ex-Lipis)
(posted 2 December 2015)
Kasumi Maru (ex-Kampar)
(posted 2 December 2015)
Dowa Maru (ex-Tung Wo)
(revised 1 July 2016)


Ex-Norwegian Vessels

Manryu Maru (ex-Bordvik)
(posted 3 January 2016)
Ex-Dutch Vessels

Chihaya Maru (ex-Tjisaroea)
(posted 3 January 2016)
Suiten Maru (ex-Schouten)
(posted 3 January 2016)
Kita Maru (ex-Gemma)
(posted 2 February 2016)




Chartered Civilian Vessels in Japanese Service as Auxiliary Transports

YAMATO MARU (ex-GIUSEPPE VERDI) Class

Yamato Maru
(posted 1 August 2014)

Bibliography of Sources

About the Authors

Mr. Gilbert Casse is a maritime historian and researcher. Retired from the aerospace industry, and later from managing Le Mans racing cars and drivers, his advocation is ship modelling, maritime photos and paintings. He resides on the SW coast of France.

Mr. Robert Hackett is a military historian and researcher. Retired from the United States Air Force and later from the aerospace industry, he resides on the coast of Florida.

Mr. Peter Cundall is a maritime historian and researcher who specializes in merchant ships. He resides in Australia and works for a towage company.

Questions to the authors concerning these TROMs should be posted on the Discussion and Questions board.