TOKUSETSU UNSOSEN ZATSUYOSEN!

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

5 May 2012

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 Un´eikai (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 9/10/2011)

SENKO MARU Class

Senko Maru
(posted 8/13/2011)
Manko Maru (revised 9/10/2011)
NACHI MARU Class

Muro Maru (posted 2/7/2009)

MYOKO MARU Class

Myoko Maru (posted 7/16/2011)
Hakkai Maru (revised 4/30/10)

KIMISHIMA MARU Class

Kimishima Maru (posted 7/23/11)

TATSUWA MARU Class

Tatsuwa Maru (posted 7/30/11)
Tatsuho Maru (posted 8/6/2011)
Tatsumiya Maru (posted 8/6/2011)
Tatsuharu Maru (posted 4/30/2010)

MUKO MARU Class

Muko Maru
(posted 8/6/2011)
Naniwa Maru (posted 8/19/2011)



MEITEN MARU Class

Meiten Maru
(posted 8/13/2011)
KAIHEI MARU Class

Kaihei Maru
(posted 8/19/2011)
Kenryu Maru (posted 8/27/2011)
KOFUKU MARU Class

Kofuku Maru (posted 9/3/2011)
KENYO MARU Class

Kenyo Maru
(posted 9/3/2011)

TOYO MARU Class

Kaisho Maru (posted 8/27/2011)
Mitakesan Maru (posted 9/10/2011)
Toyo Maru (posted 9/10/2011)
Kunishima Maru (posted 9/17/2011)
Toyo Maru No. 2 (posted 9/17/2011)
Shinyo Maru (posted 9/24/2011)

NAGARA MARU Class

Nojima Maru (posted 9/24/2011)
Noshiro Maru
(revised 11/20/10)
GENKAI MARU
Class

Choko Maru (posted 10/1/2011)
EikoMaru No. 2 Go(posted 10/1/2011)

KINAI MARU Class

Kinai Maru (posted 10/8/2011)
Hokuroku Maru (posted 10/8/2011)
Nankai Maru (revised 12/24/2011)
Hokkai Maru (posted 10/15/2011)
Tokai Maru (posted 10/22/2011)
Sanyo Maru
(revised 3/6/10)

HEITO MARU Class

Heito Maru (revised 10/29/2011)
Shoka Maru (posted 10/29/2011)
Taito Maru (posted 10/29/2011)

CUBA MARU Class

Cuba Maru (posted 11/5/11)
MIFUNE MARU Class

Mikage Maru No. 3 (posted 11/5/11)

OKITSU MARU Class

Okitsu Maru (posted 11/12/11)

SHINKYO MARU Class

Shinkyo Maru (posted 11/12/11)
Anshu Maru (posted 11/19/11)
Seikyo Maru (posted 11/19/11)
Nikkai Maru (posted 11/26/11)
Rakuto Maru (posted 11/26/11)

SHOHEI MARU Class

Shohei Maru (posted 12/2/11)

SHOAN MARU Class

Shoan Maru (posted 12/2/11)
Meiyo Maru (posted (posted 12/10/11)
SHINKO MARU Class

Yamagiri Maru (posted 12/10/11)
Keiyo Maru (revised 5/8/10)

ASAHISAN MARU Class Class

Asahisan Maru(posted 12/17/11)
Akashisan Maru (posted 12/17/11)

KOMAKI MARU Class

Kano Maru (posted 12/24/2011)
KAIKO MARU Class

Kaiko Maru (posted 12/24/2011)

SEIA MARU Class

Nana Maru (posted 2/4/2012)
Toa Maru No. 2 Go (revised 3/3/12)
KOTO MARU No. 2 GO Class

Koto Maru No. 2 Go (posted 2/4/2012)
Tamashima Maru (posted 3/3/12)
Kosei Maru (posted 3/3/12)

AZUMASAN MARU Class

Azumasan Maru (posted 3/3/12)
Amagisan Maru (posted 4/7/12)
CHOWA MARU Class

Chowa Maru (posted 4/7/12)

Nikkoku Maru (posted 4/7/12)
Nittei Maru (posted 5/5/12)
Chuwa Maru (posted 5/5/12)

HAKUBASAN MARU Class

Hakonesan Maru (posted 5/5/12)

SHOKEI MARU Class

Shokei Maru
KINE MARU Class

Kosei Maru

AKAGANE MARU Class

Akagane Maru
Kinsen Maru

KIMPOSAN MARU Class

Kimposan Maru
Kensho Maru
AMAKASU MARU Class

Tairyu Maru
Nankai Maru
No. 2

Hirotama Maru
Tatsutagawa Maru
Seizan Maru
No. 2

Shoko Maru
Katori Maru
Kizugawa Maru

KIKUKAWA MARU Class

Kirikawa Maru
Kikukawa Maru
Toei Maru

KASAGISAN MARU Class

Kasagisan Maru
HOKUYO MARU Class

Hokusho Maru

IKUTA MARU Class

Nagata Maru
Yamadori Maru

SANTO MARU Class

Santo Maru
Sansei Maru

HINO MARU No. 3 Class

Hino Maru No. 3



HIYOSHI MARU Class

Hiyoshi Maru

FUSHIMI MARU Class

Yamafuku Maru

Shinryu Maru
Tenryu Maru

KOTO MARU Class

Koto Maru
NAGISAN MARU Class

Nagisan Maru
Nasusan Maru

TARUSHIMA MARU Class

Tarushima Maru

KOKAI MARU Class

Kokai Maru



HOKKO MARU Class

Shoko Maru

KINUGASA MARU Class

Kinugasa Maru
(posted 7/17/05)
Kagu Maru (posted 4/20/07)

UNYO MARU No. 2 Class

Unyo Maru No. 2
HAGUE MARU Class

Koshin Maru

TONAN MARU No. 2 Class

Tonan Maru No. 2
(posted 4/30/2010
Tonan Maru No. 3 (revised 4/17/2010)

AKIURA MARU Class

Kozui Maru (posted 9/24/2011)
FujikawaMaru (revised 5/8/10)
LIMA MARU Class

Lyons Maru
(revised 5/8/10)
Matsumoto Maru (posted 8/6/2011)



KIRISHIMA MARU Class

Kirishima Maru (revised 4/30/10)

KAMIKAWA MARU Class

Kimikawa Maru
(revised 12/12/2009)
Kunikawa Maru (revised 9/2/09)
SHOUN MARU Class

Shoun Maru

GOSHU MARU Class

Goshu Maru (revised 6/11/11)
Goyo Maru
(revised 5/8/10)
ASAKAZE MARU Class

Kogyo Maru (posted 7/24/10)
Koshin Maru
Hitachi Maru

PEACETIME STANDARD TYPE (C) Class

Imizu Maru

Wayo Maru
Ryuko Maru
AKAGISAN MARU Class

Akibasan Maru
IKUSHIMA MARU Class

Ikushima Maru
Kasuga Maru No. 2 Go



HINO MARU No. 5 Class

Hino Maru No. 5

KANSAI MARU Class

Kanto Maru
OGASHIMA MARU Class

Ogashima Maru

DAISHIN MARU No. 1 Class

Taijun Maru
CANBERRA MARU Class

Tokyo Maru

SANTOS MARU Class

Santos Maru
(revised 3/13/10)
Montevideo Maru

KANAYAMASAN MARU Class

Kanayamasan Maru
ARATAMA MARU Class

Yamashimo Maru



TENZAN MARU Class

Tenzan Maru
Senzan Maru

SHINKOKU MARU Class

Shinkoku Maru
SHINSEI MARU No. 18 Class

Shinsei Maru No. 18

HAKONE MARU Class

Hakusan Maru
Hakozaki Maru
KEISHO MARU Class

Keisho Maru

AKASHI MARU Class

Shoei_Maru

TOYOSAKA MARU Class

Toyosaka Maru

HAKUTETSU MARU No. 15 Class

Hakutetsu Maru No. 15



HAKUTETSU MARU No. 7 Class

Hakutetsu Maru No. 7



HIDE MARU Class

Hide Maru (posted 8/21/10)

AZUMA MARU Class

Azuma Maru
(posted 1/2/2010)
YOSHINOGAWA MARU Class

YoshinogawaMaru

ARGENTINA MARU Class

Argentina Maru (revised 7/12/2009)
Brasil Maru
WARTIME STANDARD
TYPE 1E Class

Nissei Maru

FUKUYAMA MARU Class

Fukuyama Maru

NICHIYU MARU Class

Nichiyu Maru



SHINYO MARU No. 8 Class

Shinyo Maru No. 8

SUWA MARU Class

Suwa Maru
SEIZAN MARU Class

Seizan Maru

RYOTOKU MARU Class

Ryotoku Maru
KAZAN MARU Class

Tozan Maru

YOKO MARU Class

Yoko Maru

SHOEI MARU Class

Shoei Maru

Shoho Maru
HYAKUFUKU MARU Class

Hyakufuku Maru
TOSHO MARU Class

Tosho Maru

UKAI MARU No. 10 MARU Class

Unkai Maru No. 10
BUENOS AIRES MARU Class

Rio de Janeiro Maru (revised 7/2/11)

HIKAWA MARU Class

Hie Maru(revised 3/13/10)
AKAGI MARU Class

Asaka Maru (revised 2/20/10)

Awata Maru (revised 11/20/10)
HOKOKU MARU Class

Aikoku Maru
(revised 3/20/10)
Gokoku Maru (revised 3/20/10)

FUKUEI MARU No. 10 Class

Fukuei Maru No. 10
HINO MARU No. 2 Class

Hino Maru No. 2



KOWA MARU Class

Kowa Maru

CHOJO MARU Class

Choan Maru No. 2 Go
Choko Maru No. 2 Go
HIROTA MARU Class

Hirota Maru
Yoshida Maru

HIYOSHI MARU Class

Hiyoshi Maru No. 2 Go
BUSHO MARU Class

Busho Maru

NISSHO MARU No. 2 Class

Nissho Maru No. 2

NISSHO MARU No. 16 Class

Nissho Maru No. 16
JUZAN MARU Class

Juzan Maru



IWATO MARU Class

Iwato Maru

TOYO MARU No. 3 Class

Toyo Maru No. 3
NISSHO MARU No. 5 Class

Nissho Maru No. 5

NIPPONKAI MARU Class

Nipponkai Maru
(revised 6/12/2010)
ASAHI MARU Class

Asahi Maru (posted 8/20/2005)

NISSHO MARU No. 18 Class

Nissho Maru No. 18

KAMITSU MARU Class

Kunitsu Maru

NICHIEI MARU Class

Nichiei Maru



OTORI MARU Class

Otori Maru

HIKOSHIMA MARU Class

Hikoshima Maru
KAIKA MARU Class

Kaika Maru

DAICHO MARU Class

Daicho Maru
CHOI MARU Class

Choi Maru

MEISHO MARU Class

Meisho Maru

NAGOYA MARU Class

Nagoya Maru
(revised 3/13/10)

KIRI MARU No. 8 Class

Kiri Maru No. 8



SHOSEI MARU Class

Shosei Maru

KYUSHU MARU Class

Kyushu Maru
YAYOI MARU Class

Yayoi Maru

MATSUYAMA Class

Matsuyama Maru
SHINKO MARU No. 1 Class

Shinko Maru No. 1 Go

DAIGEN MARU No. 7 Class

Daigen Maru No. 7

KOGANE MARU Class

Kogane Maru


KIYOSUMI MARU Class

Kiyosumi Maru
(revised 8/20/10)


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

Ex-American Vessel s

Paran Maru (ex-Palawan)
Hokuhi Maru (ex-Cetus)
Anan Maru (ex-Anakan)


Ex-British Vessels

Nichirin Maru (ex-Mata Hari)
Hoki Maru (ex-Hauraki)
Kembu Maru (ex-Empire Blossom)
Keishu Maru (ex-Henry Keswick)
Risui Maru (ex-Lipis)
Kasumi Maru (ex-Kampar)


Ex-Norwegian Vessels

Manryu Maru (ex-Bordvik)

Ex-Dutch Vessels

Chihaya Maru (ex-Tjisaroea)
Kyoko Maru (ex-Schouten)
Kita Maru (ex-Gemma)

Bibliography of Sources

About the Authors

Mr. Gilbert Casse is a maritime historian and researcher. Retired from 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.

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