Japanese Aircraft Transports

KOKUKI-UMPANSEN!

(KEIYO MARU prewar)

IJN KEIYO MARU: Tabular Record of Movement
© 2007-2024 Bob Hackett, Sander Kingsepp and Peter Cundall.
Revision 8

14 April 1937:
Yokohama. Laid down at Mitsubishi Heavy Industries’ shipyard.
23 August 1937:
Launched and named KEIYO MARU.
15 November 1937:
Completed.
19 January 1938:
Arrives at the Panama Canal from Iloilo, PI with 4250 tons sugar and general cargo. Transits the canal and departs for Baltimore, MD.
21 February 1938:
Arrives at the Panama Canal from Boston, Mass with 7753 tons steel and phosphates. Transits the canal and departs for Dairen.
8 July 1938:
Arrives at the Panama Canal from Baltimore, MD with 7095 tons lubricating oil and general cargo. Transits the canal and departs for Kobe.
20 October 1938:
Arrives at the Panama Canal from Kirun (Keelung), Taiwan with 8633 tons sugar and general cargo.
21 October 1938:
Departs the Panama Canal for Philadelphia.
8 December 1938:
Arrives at the Panama Canal from Philadelphia, PA with 8016 tons steel and general cargo. Transits the canal and departs for Kobe.
27 March 1939:
Arrives at the Panama Canal from Iloilo, PI with 7578 tons sugar and general cargo. Transits the canal and departs for New Orleans, LA.
10 May 1939:
Arrives at the Panama Canal from New Orleans with 7894 tons gasoline, phosphate and general cargo. Transits the canal and departs for Yokohama.
26 August 1939:
Arrives at the Panama Canal from Iloilo, PI with 7240 tons sugar and general cargo. Transits the canal and departs for New Orleans.
8 October 1939:
Arrives at the Panama Canal from Port Arthur, Texas with 8321 tons phosphate, coffee and cocoa. Transits the canal and departs for Kobe.
12 August 1941:
Requisitioned. Begins conversion to an armed auxiliary aircraft transport. 120-mm (4.7-inch) guns are installed at the bow and the stern.
21 October 1941:
Completes conversion. Registered in the IJN. Recalled Captain (Ret) (later Rear Admiral) Ikeuchi Masamichi (40)(former CO of CHITOSE) is the CO.
16 November 1941:
Departs Takao for the southern China area and French Indochina.
1 December 1941:
In Vice Admiral (later Admiral) Tsukahara Nishizo's (36)(former CO of AKAGI) 11th Air Fleet's Supply Unit. Departs Takao.
4 December 1941:
Arrives at Mako, Pescadore Islands.
7 December 1941: Operation "M" - The Invasion of the northern Philippines:
At 1630 departs Mako in Vice Admiral Takahashi Ibo’s (36) (former CO of YAMASHIRO) Philippines Seizure Force, landing force also consisting of IJA transports AKIURA, ARIZONA, KAZUURA, KURAMA, MATSUKAWA and YUZAN MARUs. The Army transports carry Col. H. Tanaka 1st Raiding Force Detachment consisting of two companies of the 1st Battalion and the 2nd Battalion, 2nd Formosan Infantry Regiment, 48th Division. Other units transported are the 11th IJAAF regiment, elements of the 28th and 40th Ground Support Airbases (Battalion size), one company of the 9th Ground Support Depot Airbase, the 40th AA Detachment, the 123th, 297th and 298th truck companies, the 56th Labor Construction Company, two Aviation Signal Air Defense detachments and one Weather Aviation Meteorological company.
Escort is provided by Rear Admiral Hara Kezaburo (37) in Light Cruiser NATORI (F) with destroyers ASAKAZE, HARUKAZE, HATAKAZE, MATSUKAZE (Desdiv 5), FUMITSUKI, MINATSUKI, NAGATSUKI and SATSUKI (DesDIv 22), minesweepers W-15, W-16 and W-19 (MineSweepDiv 11), auxiliary gunboats MANYO, TOMITSU and TAIKO MARUs (GunboatDiv 2) and subchasers CH-1, CH-2 and CH-3 (SubChaseDiv 1) and CH-13, CH-14 and CH-15 (SubChaseDiv 2).
10 December 1941:
At 0550, arrives off Aparri for the invasion landings.
13 December 1941:
Departs Aparri.
16 December 1941:
Arrives at Takao, Formosa.
31 December 1941:
Departs Takao to Mako.
1 March 1942:
Arrives at Kendari, Celebes. Probably delivers Mitsubishi A6M "Zeke" A6M fighters supplies, personnel and munitions.
5 March 1942:
Supplies provisions to hospital Ship ASAHI MARU.
7 March 1942:
Departs Kendari.
14 March 1942:
Arrives at Furue.
15 March 1942:
Departs Furue.
18 March 1942:
Arrives at Kisarazu and probably loads A6M fighters, then departs across Tokyo Bay for Yokohama and Yokosuka.
22 March 1942:
Transfers from Yokohama to Yokosuka.
14 April 1942:
Departs Yokohama and arrives at Yokosuka.
16 April 1942:
Departs Yokosuka and later that day arrives at Uraga.
20 April 1942:
Departs Uraga and later that day arrives at Yokosuka.
28 April 1942:
Departs Yokosuka and transfers to Kisarazu. Probably loads A6M fighters.
29 April 1942:
Departs Kisarazu.
3 May 1942:
Arrives at Marcus Island (Minami Torishima) located between Midway and the Bonin Islands - about 1,000 miles from Tokyo. Probably delivers Type 96 A5M Claude fighters or A6M fighters.
5 May 1942:
Departs Marcus Island.
10 May 1942:
Arrives at Kisarazu. Probably unloads damaged A6M fighters.
11 May 1942:
Departs Kisarazu.
12 May 1942:
Arrives at Yokosuka.
15 May 1942:
Departs Yokosuka and later that day arrives at Kisarazu. Probably loads A6M fighters.
17 May 1942:
Departs Kisarazu.
18 May 1942:
Arrives at Yokosuka. That same day, KEIYO MARU is assigned to Vice Admiral (later Admiral) Tsukahara Nishizo’s (36)(former CO of AKAGI) 11th Air Fleet with LYONS and NAGOYA MARUs.
19 May 1942:
Departs Yokosuka in a convoy also consisting of MEIYO, AZUMA and HOKUROKU MARUs escorted by destroyers KAGERO and ARARE. The convoy carries the 11th Construction Unit.
24 May 1942:
Arrives at Saipan.
28 May 1942: Operation “MI” -The Battle of Midway:
In the evening, KEIYO MARU departs Saipan in Vice Admiral (later Admiral) Kondo Nobutake's (35)(former CO of KONGO) Midway Invasion Force as part of Rear Admiral (later Vice Admiral) Tanaka Raizo's (41)(former CO of KONGO) Transport Group with TOA MARU No. 2, KIYOSUMI, ZENYO, ARGENTINA, BRAZIL, AZUMA, GOSHU, HOKUROKU, KANO, KIRISHIMA and NANKAI MARUs and oiler AKEBONO MARU escorted by Tanaka's DesRon 2’s light cruiser JINTSU with DesDiv 15’s KUROSHIO, OYASHIO, DesDiv 16’s AMATSUKAZE, HATSUKAZE, TOKITSUKAZE, YUKIKAZE and DesDiv 18’s destroyer-transports ARARE, KASUMI and SHIRANUHI.
Rear Admiral (later Vice Admiral) Fujita Ruitaro's (38)(former CO of FUSO) Seaplane Tender Division 11’s CHITOSE and KAMIKAWA MARU provide air cover.
3 June 1942:
At about 1700, the convoy is attacked by LtCol (later General) Walter C. Sweeney's nine Boeing B-17 "Flying Fortress" heavy bombers from Midway, but they score no hits.
4 June 1942:
About 2354 (JST), the convoy is attacked by four torpedo-carrying Consolidated PBY-5A "Catalina" amphibious patrol planes of Patrol Squadron 24 from Midway. Lt William L. Richards, the flight leader of the mission, scores a hit on AKEBONO MARU's bow with an obsolete Mark-XIII Mod 1 torpedo at 26-34N, 174-14W. The torpedo hit detonates AKEBONO MARU's AA shell magazine and tears a 10-meter long gash in her side. KIYOSUMI MARU is strafed, but KEIYO MARU is undamaged.
13 June 1942:
Arrives at Truk.
22 June 1942:
Departs Saipan.
25 June 1942:
Damaged by two torpedo hits at 127 degrees 35 nautical miles off Nojima Lighthouse. [1]
4 July 1942:
Departs Yokosuka.
28 July 1942:
Departs Saipan.
2 August 1942:
Arrives at Yokkaichi. Probably loads aviation gasoline at the refinery.
5 August 1942:
Departs Yokkaichi.
6 August 1942:
Arrives at Yokohama.
10 August 1942:
Departs Yokohama.
15 August 1942:
Arrives at Saipan.
18 August 1942:
Departs Saipan.
24 August 1942:
Arrives at Rabaul.
29 August 1942:
Departs Rabaul.
8 September 1942:
Arrives at Yokkaichi. Probably loads aviation gasoline at the refinery.
10 September 1942:
Departs Yokkaichi.
11 September 1942:
Arrives at Yokosuka.
24 September 1942:
Departs Yokosuka and later that day arrives at Kisarazu.
25 September 1942:
Departs Kisarazu and later that day arrives at Yokosuka.
26 September 1942:
Departs Yokosuka.
6 October 1942:
Arrives at Rabaul, New Britain. Probably delivers A6M fighters to the Tainan Naval Air Group of the 25th Air Flotilla.
13 October 1942:
Departs Rabaul.
14 October 1942:
Arrives at Buka, Bougainville. Probably delivers A6M fighters.
15 October 1942:
At 1500 departs Buka escorted by patrol boat PB-34.
16 October 1942:
At 0900 arrives at Buin, Bougainville. Probably delivers A6M fighters and departs later that day.
17 October 1942:
Arrives at Shortland, Bougainville. Probably delivers A6M fighters.
20 October 1942:
Departs Shortland.
21 October 1942:
Arrives at Rabaul.
25 October 1942:
Recalled Captain (Ret)(Rear Admiral, posthumously) Miyamoto Sadachika (39)(former CO of YAEYAMA) assumes command.
29 October 1942:
Departs Rabaul for an unknown destination.
1 November 1942:
Arrives at Rabaul.
2 November 1942:
Departs Rabaul.
3 November 1942:
Arrives at Buin. Probably delivers A6M fighters.
11 November 1942:
Departs Buin.
12 November 1942:
Arrives at Rabaul.
17 November 1942:
Departs Rabaul.
29 November 1942:
Arrives at Yokohama.
30 November 1942:
Transfers from Yokohama to Yokosuka.
23 December 1942:
Departs Yokohama.
17 January 1943:
At 1600, departs Rabaul for Buka, Buin and Ballale, Bougainville. Probably delivers A6M fighters before returning to Rabaul.
25 January 1943:
Departs Shortland for Rabaul.
2 February 1943:
Near Shortland Islands, Bougainville. At 0130, auxiliary subchaser CHa-30 joins as escort. At 1500, USAAF B-17 heavy bombers launch bomb and damage KEIYO MARU. Arrives at Shortland at 1630.
9 February 1943:
Departs Buin for the Shortland, Rabaul and Truk. Probably delivers A6M fighters.
17 February 1943:
At 1700 departs Buin for Rabaul.
18 February 1943:
Off New Britain. LtCdr John R. Craig's (USNA ’30) USS GRAMPUS (SS-207) torpedoes and lightly damages KEIYO MARU at 04-55S, 152-26E. [2][3]
19 February 1943:
SE of New Britain. Craig again closes on KEIYO MARU and torpedoes her with unknown results. [3]
24 February 1943:
Rabaul. Temporary repairs by HAKKAI MARU are undertaken before the ship departs Rabaul for Truk.
11 March 1943:
At Truk repair ship AKASHI undertook more permanent repairs.
18 March 1943:
Departs Saipan for Chichijima and Yokosuka.
22 March 1943:
At 0440 departs Truk for Kure escorted by destroyer ISOKAZE and cable layer escorts HASHIMA and TATEISHI.
25 March 1943:
At 1030 arrives at Saipan. ISOKAZE is detached.
30 March 1943:
Departs Saipan escorted by cable layer escorts HASHIMA and TATEISHI and for part of the way by auxiliary subchaser KYO MARU No. 8.
3 April 1943:
Arrives at Chichijima, Bonin Islands.
6 April 1943:
Captain Takashimada Masaki (35)(former CO of TSUGA) is appointed CO.
8 April 1943:
Departs Chichijima.
11 April 1943:
Arrives at Yokosuka.
27 May 1943:
Transfers from Yokosuka to Yokohama.
28 June 1943:
Yokohama. Enters Asano dockyard for permanent repairs to damage from earlier torpedo attack.
25 October 1943:
Repairs are completed.
29 October 1943:
At 0930 transfers from Yokohama to Yokosuka.
8 November 1943:
Departs Yokosuka, probably for post-repair trials. Crosses bay to Kisarazu. Loads aircraft.
9 November 1943:
At 1220 transfers from Kisarazu to Yokosuka.
14 November 1943:
At 1400, KEIYO MARU departs Yokosuka in fleet convoy No. 3115 with transport HEIAN MARU and food stores ship IRAKO escorted by destroyer YUKIKAZE and kaibokan OKI. KEIYO MARU is probably carrying A6M fighters and spare aircraft engines.
16 November 1943:
Lookouts on HEIAN MARU sight a submarine traveling in the opposite direction (probably USS DACE (SS-247).
19 November 1943:
At 0724 (JST), the convoy is attacked by LtCdr (later Captain/victor of SHINANO) Joseph Enright's (USNA ’33) USS DACE on her first patrol. Enright targets HEIAN MARU. A torpedo barely misses the bow of OKI. The kaibokan counter-attacks with depth-charges. HEIAN MARU also drops a DC, but USS DACE escapes undamaged as does KEIYO MARU.
23 November 1943:
Arrives at Truk at 1550.
1 December 1943:
At 0700 KEIYO MARU departs Truk in convoy No. 1013 consisting of aircraft transport NAGOYA MARU, transport YAMAKUNI MARU (ex YAMAKAZE MARU) escorted by subchasers CH-16, CH-20, CH-29 and CH-40. KEIYO and NAGOYA MARUs are probably carrying A6M fighters and spare aircraft engines.
5 December 1943:
At 1510 arrives at Rabaul. Probably delivers A6M fighters, personnel and supplies for the 253rd Naval Air Group.
22 December 1943:
At 0110, KEIYO MARU departs Rabaul with fleet convoy No. 2222 consisting of YAMABIKO and YAMAKUNI (ex-YAMAKAZE MARU) MARUs escorted by destroyers OITE and ASANAGI.
25 December 1943:
Arrives at Truk at 1657.
1 January 1944:
KEIYO MARU is reassigned to the Ministry of Transport.
2 January 1944:
At 0430 KEIYO MARU departs Truk for Yokosuka in convoy No. 4102 also consisting of repair ship YAMABIKO MARU and cargo ship YAMAKUNI MARU escorted by destroyer ASAKAZE, kaibokan MANJU, cable layer HATSUSHIMA and minesweeper W-24.
10 January 1944:
185 miles NW of Torishima, Ogasawara (Bonins). At about 0600, in typhoon weather conditions, LtCdr (later Rear Admiral-Ret) David L. Whelchel's (USNA ’30) USS STEELHEAD (SS-280) fires four torpedoes in a night surface radar attack and hits YAMABIKO MARU in the engine room. YAMAKUNI MARU takes YAMABIKO MARU in tow.
11 January 1944:
KEIYO MARU arrives at Tateyama.
12 January 1944:
At 0630 departs Tateyama and at 0930 KEIYO MARU arrives at Yokosuka.
14 January 1944:
NW of Hachijo-Jima. At about 0040, Captain (later Rear Admiral) Karl G. Hensel's (USNA ’23) USS SWORDFISH (SS-280) torpedoes and sinks YAMAKUNI MARU with the loss of 18 of her crew. Shortly thereafter, YAMABIKO MARU also sinks. Five crewmen are KIA. The escorts drop 24 depth charges and damage USS SWORDFISH, but Hensel manages to escape.
18 January 1944:
Captain Kondo Saburo (46) assumes command.
21 January 1944:
Yokosuka Naval Dockyard. Begins reconversion to a general transport.
5 February 1944:
The reconversion is completed.
29 February 1944:
Departs Yokosuka.
3 March 1944:
Departs Truk escorted by kaiboikan MANJU.
5 March 1944:
At 0800, departs Chichijima in the "Higashi Matsu" No. 1A convoy consisting of TATSUHARU and BINGO MARUs escorted by kaibokan MANJU, OKI and auxiliary subchaser TAKUNAN MARU No. 8.
12 March 1944:
At 1200, arrives at Truk.
28 March 1944:
Departs Saipan for Yokosuka in convoy No. 4328 also consisting of auxiliary transport IKUSHIMA MARU escorted by minesweeper W-20.
5 April 1944:
Arrives at Yokosuka.
3 May 1944:
Departs Yokosuka.
4 May 1944:
At 1400, KEIYO MARU departs Tateyama in convoy No. 3503 consisting of HAKOZAKI, HIYORI (NICHIWA), ENOSHIMA, MINO, OSAKA, TAIKOKU, FUKKO, TATSUTAGAWA, SHINFUKU, FUKOKU, KOHO, KOJUN and SHUNSEN MARUs escorted by destroyers ASANAGI, MINATSUKI, torpedo boat OTORI, kaibokan OKI and CD-24, subchasers CH-31, CH-32, CH-52 and auxiliary subchaser SHONAN MARU No. 8.
10 May 1944:
420 miles NW of Saipan. At 1743, LtCdr Russell Kefauver’s (USNA ’33) USS TAMBOR (SS-198) torpedoes and damages KEIYO MARU at 19-27N 140-00E. No. 2 and No. 3 holds flood. 97 crewmen and passengers are KIA.
14 May 1944:
Arrives at Saipan. Repairs are delayed.
11 June 1944:
Fear of an imminent Allied landing causes all navigable ships in Saipan to flee. At 0400, KEIYO MARU departs Saipan in makeshift convoy No. 4611 consisting of MOJI, FUKOKU, BATAVIA, TENRYUGAWA, TATSUTAGAWA, KOKKO, IMIZU, SHINTO, HINKO, BOKUYO, NITCHO, REIKAI, INARI MARUs and 16 other unidentified ships escorted by torpedo boat OTORI, kaibokan CD-4, subchasers CH-33, CH-55, auxiliary subchasers CHa-20, CHa-50 and auxiliary minesweeper Wa-6.
12 June 1944:
About 100 nautical miles W of Alamagan Island, northern Marianas. At 0935, Vice Admiral (later Admiral) Marc A. Mitscher’s (USNA ’10) Task Force 58’s carriers USS ESSEX (CV-9), USS LANGLEY (CVL-27) and USS COWPENS (CVL-25) attack the convoy. They sink transports BATAVIA 59 crewmen and 18 passengers KIA), HINKO (actually sank after air attack 25 June and submarine attack 19 July nine crewmen and 12 passengers KIA), SHINTO (KAMISHIMA) (53 crewmen and 54 passengers KIA), IMIZU (67 crewmen KIA), NITCHO (14 crewmen KIA), REIKAI (40 crewmen and 42 passengers KIA) and TENRYUGAWA (seven crewmen KIA) MARUs, cargo ships BOKUYO (45 crewmen KIA), FUKOKU (51 crewmen and 31 passengers KIA), and MOJI (53 crewmen and five gunners KIA), torpedo boat OTORI (casualties unknown) and auxiliary netlayer KOKKO MARU (two crewmen KIA). Mitscher’s planes damage transport TATSUTAGAWA MARU, kaibokan CD-4, subchasers CH-33, CH-50 and CH-51, auxiliary subchaser Cha-20 and auxiliary minesweeper Wa-6.
Grumman F6F "Hellcat" fighter-bombers from Rear Admiral William K. Harrill's (USNA ’14) TG 58.4's (USS ESSEX, USS LANGLEY and USS COWPENS) also damage KEIYO MARU that is then beached off Garapan. Casualties are unknown. Undoubtedly, Captain Kondo and his surviving crewmen are later conscripted into the ranks of Saipan's defenders.
13 June 1944:
Mitscher’s attacks on Saipan and surrounding areas continue. TF 58's planes finish off KEIYO MARU.
15 June 1944: American Operation "Forager" - The Invasion of Saipan:
Vice Admiral (later Admiral) Richmond K. Turner's (USNA ’08) (former CO of AUGUSTA, CA-31) Task Force 52 lands Marine LtGen Holland M. Smith's V Amphibious Corps and the invasion of Saipan begins.
8 July 1944:
Captain Kondo is KIA. He is promoted Rear Admiral, posthumously. [4]
1944:
Removed from the Navy List.

Authors' Note:
[1] The attacker most probably was LtCdr (later Rear Admiral, Ret) William H. Brockman, Jr's (USNA ’27) big USS NAUTILUS (SS-168). The damage may have been caused by dud or premature explosions of Mark 14 torpedoes and must have been slight based on KEIYO MARU's subsequent activities.
[2] Again, the damage may have been caused by a dud or premature explosion of a Mark 14 torpedo and must have been slight since KEIYO MARU did not receive permanent repairs until late Jun '43.
[3] Aircraft from 958th Naval Air Group, probably E13A1 Jakes", may have sunk USS GRAMPUS on this day, or possibly USS GRAMPUS was lost on 5/6 Mar '43 in the Blackett Strait in an attack by destroyer MINEGUMO. USS GRAMPUS was declared missing and presumed lost with all hands on 3 Mar '43.
[4] On 7 July '44, the largest banzai charge of the Pacific War took place on Saipan. Three thousand Japanese soldiers attacked a U.S. Army division and overran two battalions killing or wounding 650 Americans before the Japanese were annihilated. Kondo and his men were probably KIA in one of the final suicide attacks. On 9 July '44, Saipan fell.
Photo credit and grateful thanks for general assistance goes to Gilbert Casse of France. Thanks also to Mr. Matt Jones of USA for help in identifying CO's.
- Bob Hackett, Sander Kingsepp and Peter Cundall.

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