Japanese Minelayers

FUSETSUKAN!
(KOEI MARU, prewar)

IJN Minelayer KOEI MARU: Tabular Record of Movement
© 2014 Bob Hackett

11 February 1933:
Nagasaki. Laid down Mitsubishi Zosen, K. K. as Yard No. 550, a 6,774 ton cargo ship for Taiyo Kaiun’s subsidiary Takachiho Shosen, K. K. of Kobe.
3 September 1933:
Launched and named KOYEI MARU
10 January 1934:
Completed and placed on Takachiho Shosen’s Nagasaki-Darien Line’s regular Pacific routes.
1938:
Renamed KOEI MARU.
15 August 1941:
Nagasaki. Requisitioned by the IJN and attached to the Yokosuka Naval District. That same day, begins conversion to an auxillary minelayer at Mitsubishi Zosen, K. K. Recalled retired Captain (Rear Admiral, posthumously) Suzuki Kozo (36)(former CO of JINTSU) is appointed Commanding Officer.
20 September 1941:
Completes conversion.
30 September 1941:
Departs Yokosuka.
6 December 1941:
Arrives at Truk.
10 December 1941:
Truk. Attached to Vice Admiral Moizumi Shinichi’s (37)(former CO of MAYA) 4th Base Force.
26 December 1941:
Departs Truk for Greenwich (Kapingamarangi) Island (southernmost Island in the Carolines). [1]
2 January 1942:
Arrives at Greenwich Island.
5 January 1942:
Departs Greenwich Island for Truk.
6 January 1942:
Arrives at Greenwich Island.
13 January 1942:
Departs Greenwich Island for Truk.
15 January 1942:
Arrives at Greenwich Island
17 January 1942:
Departs Truk for Greenwich Island.
20 January 1942:
Arrives at Truk.
28 January 1942:
Truk. Lays mines in the area.
31 January 1942:
Departs Truk.
1 February 1942:
Arrives at Ponape.
2 February 1942:
Arrives at Greenwich Island.
4 February 1942:
KOEI MARU departs Greenwich for Rabaul.
6 February 1942:
Arrives at Rabaul.
20 February 1942: Aborted American Raid on Rabaul:
Rear Admiral (later Vice Admiral-Ret) Wilson Brown Jr’s (USNA '02)(later Presidents Roosevelt and Truman’s Naval Aide) Task Force 11 (USS LEXINGTON, CV-2), is en route to attack Rabaul. At 1030, the task force is spotted by a Kawanishi Type 97 "Mavis"H6K flying boat of the Yokohama Naval Air Group. Since surprise is lost, the American attack is cancelled.
At 1430, an a Aichi Navy Type 0 "Jake" E13A reconnaissance seaplane from tender KIYOKAWA MARU's Air Unit takes off from Rabaul. At 1815, its crew sends a sighting report that places TF 11 470 miles NNE of Rabaul. TF 11 is attacked off Bougainville by the 4th NAG’s land-based bombers, but the Japanese are beaten off with heavy losses.
At 2000, the Jake signals it is returning to Rabaul, but fails to arrive.
21 February 1942:
The Japanese command at Rabaul orders KOEI MARU to search for the lost floatplane in the waters NW of Greenwich Island and minelayer TSUGARU to search the Tanga and Nuguria Islands.
22 February 1942:
KOEI MARU departs Rabaul for Palau.
23 February 1942:
TSUGARU picks up three 4th NAG’s survivors and departs at 0800. By 1200, she arrives at Rabaul.
5 March 1942:
KOEI MARU arrives at Palau
10 March 1942:
Departs Palau
14 March 1942:
Arrives at Truk.
28 April 1942: Operation “MO” – The Invasion of Tulagi and Port Moresby:
KOEI MARU departs Truk in Rear Admiral Shima's Tulagi Invasion Force with minelayer OKINOSHIMA (F) and transport AZUMASAN MARU escorted by DesDiv 23's KIKUZUKI and YUZUKI, subchasers TOSHI MARU No. 3 and TAMA MARU No. 8 and auxiliary minesweepers Wa-1 and Wa-2, HAGOROMO MARU, NOSHIRO MARU No. 2 and TAMA MARU.
3 May 1942:
Tulagi. Shima disembarks troops of the No. 3 Kure Special Naval Landing Force (SNLF).
4 May 1942:
100 miles S of Guadalcanal. Task Force 17's Rear Admiral (/later Admiral) Frank J. Fletcher (USNA '04/MOH '14) receives a signal that IJN transports are disembarking troops and equipment at Tulagi. At 0701, USS YORKTOWN (CV-5) launches her first surprise strike on Shima's Invasion Force. The strike consists of 18 Grumman F4F-3 "Wildcats" fighters of VF-42, 12 Grumman TBD-1 “Devastator” torpedo-bombers of VT-5 and 28 Douglas SBD-3 “Dauntless” dive-bombers from VS-5 and BY-5.
Purvis Bay, Florida Island, Solomons. TBDs torpedo and sink destroyer KIKUZUKI. Auxiliary minesweepers Wa-1 and Wa-2 and four barges are also sunk. YORKTOWN's planes also damage KOEI MARU, destroyer YUZUKI, transport AZUMASAN MARU and five floatplanes. OKINOSHIMA is damaged by near misses. TAMA MARU is damaged and sinks two days later. YUZUKI is strafed.
10 May 1942: The Seizure of Ocean-Nauru (Operation “RY”):
KOEI MARU departs Rabaul in the Ocean-Nauru Occupation Force also consisting of minelayer TSUGARU and transports KINRYU and KOZUI MARUs escorted by CruDiv 18’s light cruiser TATSUTA and DesDiv 30’s MOCHIZUKI, UZUKI and YUZUKI.
15 May 1942:
Operation "RY" is cancelled.
19 May 1942:
Arrives at Rabaul.
21 May 1942:
Departs Rabaul. 25 May 1942:
Arrives at Truk.
1 June 1942:
Departs Truk.
7 June 1942:
Arrives at Yokosuka. Docked for repairs to her hull, engines and weapons.
1 July 1942:
Departs Yokosuka.
15 July 1942:
Arrives at Truk.
25 July 1942:
Departs Truk on a transport mission.
31 July 1942:
Arrives back at Truk.
1 August 1942:
Departs Truk on a transport mission.
8 August 1942:
Arrives back at Truk.
26 August 1942: The capture of Ocean and Nauru islands:
KOEI MARU departs Truk for Nauru in a convoy also consisting of transport HAKOZAKI MARU escorted by CruDiv 18’s light cruiser YUBARI and DesDiv 29's YUNAGI.
30 August 1942:
Arrives at Nauru.
31 August 1942:
Following the landings at Nauru and Ocean islands, the convoy proceeds to Jaluit.
3 September 1942:
Departs Jaluit.
1 October 1942:
Arrives at Truk.
5-11 October 1942:
Truk. Undergoes updates to her mine laying gear.
14 November 1942:
Truk. Moves to Uman (Fuyu Shima) anchorage, then to Dublon (Natsu Shima) anchorage.
19 November 1942:
Departs Truk on a transport mission.
8 December 1942: Arrives back at Truk.
14 December 1942:
Departs Truk on a transport mission.
3 January 1943:
Arrives back at Truk.
17 January 1943:
Recalled retired Captain Watanabe Osamu is appointed Commanding Officer.
18 January 1943:
Departs Truk.
22 January 1943:
Arrives at Nauru.
23 January 1943:
Departs Nauru.
24 January 1943:
Arrives at Tarawa Island. Unloads air base construction materials.
27 January 1943:
Departs Tarawa.
1 February 1943:
Arrives at Truk.
15 February 1943:
Departs at Truk.
19 February 1943:
Arrives at Nauru
23-24 February 1943:
Departs Nauru and arrives at Ocean Island.

24-25 February 1943:
Departs Ocean Island and arrives at Tarawa, Gilberts.
3 March 1943:
Departs Tarawa.
9 March 1943:
Arrives at Saipan, Marianas.
14 March 1943:
Departs Saipan, Marianas with transport TOKYO MARU and an unknown escort.
21 March 1943:
Arrives at Yokosuka
2 April 1943:
Departs Yokosuka
10 April 1943:
Arrives at Truk.
3 May 1943:
Departs Truk.
7 May 1943:
Arrives at Nauru and departs.
10 May 1943:
Arrives at Tarawa.
13 May 1943:
Departs Tarawa.
18 May 1943:
Arrives at Truk.
21 May 1943:
KOEI MARU’s anti-submarine mines are set for deep water off Korea and the SW coast of China.
2 June 1943:
KOEI MARU departs Truk in convoy No. 4602. also consising of ammunition ship NARUTO MARU escorted by torpedo boat HIYODORI.
7 June 1943:
Arrives at Saipan and departs.
10 June 1943:
Arrives at Yokosuka.
24 June 1943:
Departs Yokosuka
9 July 1943:
Arrives at Maizuru.
15 July 1943:
At 0500, KOEI MARU departs Maizuru with auxiliary minelayer SHINKO MARU.
27 July 1943:
Arrives at Maizuru.
3 August 1943:
At 0500, KOEI MARU departs Maizuru with armed merchant cruiser SAIGON MARU and minelayer SHINKO MARU.
14 August 1943:
Returns to Maizuru.
18 August 1943:
At 0700, KOEI MARU departs Maizuru with AMC SAIGON MARU and minelayer SHINKO MARU.
31 August 1943:
Arrives at Sasebo.
7 September 1943:
Departs Sasebo.
16 September 1943:
Arrives at Yura
19 September 1943:
Departs Yura.
23 September 1943:
At Kii Strait.
26 September 1943:
Arrives at Kure .
19 October 1943:
Attached to the Kure Guard Unit.
26 October 1943:
Departs Kure.
27 October 1943:
Arrives at Saeki.
1 November 1943:
Departs Saeki.
6 November 1943:
Returns to Saeki.
10 November 1943:
Departs Saeki.
16 November 1943:
Ownership of KOEI MARU transfers to Daido Marine Transport Co., Ltd.
7 December 1943:
Arrives at Yokosuka.
29 December 1943:
Conducts maneuvers under the direction of the Sasebo Guard Unit's squadron commander .
30 December 1943:
Ordered to support anti-submarine mining S of Tokai in the middle of January
2 January 1944:
Departs Yokosuka and arrives at Mutsure Island.
6 January 1944:
Departs Mutsure Island and arrives at Sasebo.
20 January 1944:
Attached to the 18th squadron
23 January 1944:
Departs Sasebo.
24 January 1944:
Supports anti-submarine mining S of Tokai then dearts the area.
25 January 1944:
Arrives at Sasebo and departs and arrives at Arikawa Bay.
26 January 1944:
Departs Arikawa Bay.
27 January-5 February 1944:
Arrives at Saeki. Loads mines.
6 February 1944:
Departs Saeki.
7 February 1944:
Arrives at Sasebo.
13 February 1944:
Departs Sasebo and arrives at Ebisu Bay in heavy weather .
17 February 1944:
Departs Ebisu Bay
18 February 1944:
Supports anti-submarine mining S of Tokai then departs the area.
20 February 1944:
Arrives at Saeki.
26 February 1944:
Departs Saeki.
27 February 1944:
Arrives at Sasebo. That same day, KOEI MARU and minelayer TOKIWA escorted by kaibokan CD-29, CD-22 and CD-68 lay a minefield of 1,000 mines S of Yakushima.
3 March 1944:
Departs Sasebo and arrives at Ebisu Bay
6 March 1944:
Arrives at Terashima Strait
7 March 1944:
Arrives at Ebisu Bay
12 March 1944:
Departs Ebisu Bay
13 March 1944:
Conducts anti-submarine mining SE of Tokai then departs the area and returns to Ebisu Bay
15 March 1944:
Departs Ebisu Bay.
15 March 1944:
Arrives at Sasebo.
16 March 1944:
Loads mines and food then refuels.
22 March 1944:
Departs Sasebo and arrives at Ebisu Bay
23 March 1944:
Departs Ebisu Bay.
24 March 1944:
Conducts anti-submarine mining SE of Tokai then departs the area
25 March 1944:
Arrives at Sasebo.
26 March-2 April 1944:
Arrives at Sasebo Navy Yard. Fitted with additional 25-mm machine guns. Minelaying machinery updated.
4 April 1944:
Departs Sasebo and arrives at Ebisu Bay
4 April 1944:
Departs Ebisu Bay.
5 April 1944:
Arrives at Saeki
6-9 April 1944:
Loads mines.
10 April 1944:
Departs Saeki
11 April 1944:
Arrives at Sasebo
17 April 1944:
Departs Sasebo and arrives at Ebisu Bay
18 April 1944:
Arrives at Terashima Strait. Departs and arrives at temple island strait.
20 April 1944:
Departs temple island strait.
29 April 1944:
Arrives at Sasebo
5-6 April 1944:
Arrives at Saeki
6-9 April 1944:
Loads mines.
10 April 1944:
Departs Saeki
11 April 1944:
Arrives at Sasebo
17 April 1944:
Departs Sasebo and arrives at Ebisu Bay
18 April 1944:
Arrives at Terashima Strait.
23-24 April 1944:
Arrives at Kirun, Formosa (Keelung. Taiwan).
26 April 1944:
Departs Keelung
28 April 1944:
Arrives at Ebisu Bay and departs.
29 April 1944:
Arrives at Sasebo and departs.
1 May 1944:
Arrives at Moji.
2 May 1944:
KOEI MARU is attached to the Takao, Formosa Guard Unit.
4-5 May 1944:
Arrives at Saeki . Loads mines.
5 May 1944:
Departs Saeki .
6 May 1944:
Arrives at Sasebo.
10 May 1944:
KOEI MARU departs Sasebo as part of the 18th Squadron consisting of auxiliary gunboat (ex-AMC) SAIGON MARU, minelayers TOKIWA (F) and SHINKO MARUs and small minelayer TAKASHIMA escorted by torpedo boat TOMOZURU, subchaser CH-58 and patrol boat KAII (ex HAI WEI). Later, that day, arrives at Ebisu Bay
11 May 1944:
Departs Ebisu Bay
14 May 1944:
Arrives at Mako, Pescadores.
16 May 1944:
Arrives at Kirun.
3 June 1944:
Arrives at Sasebo
15 June 1944:
Departs Sasebo.
16 June 1944:
Arrives at Ebisu Bay.
17 June 1944:
Departs Ebisu Bay.
19-20 June 1944:
Off Okinawa. The 18th Squadron consisting of auxiliary gunboat (ex-AMC) SAIGON MARU, minelayers TOKIWA and SHINKO MARUs and small minelayer TAKASHIMA, lays 1,650 mines. Torpedo boat TOMOZURU, subchaser CH-58 and patrol boat KAII provide escort. Later, departs the Okinawa area.
22 June 1944:
Arrives at Sasebo.
28 June 1944:
New CO, Captain Takahashi arrives
28 June 1944:
Loads transport cable, heavy oil and food.
1 July 1944:
Loads heavy oil.
5-6 July 1944:
Loads various items.
6 July 1944:
Loads mines.
7 July 1944:
Loads mines and depth charges.
8 July 1944:
Departs Sasebo and arrives at Ebisu Bay. Later that day, arrives at Sasebo and loads mines and.depth charges.
9 July 1944:
Loads food.
10 July 1944:
Departs Sasebo and arrives at Mutsure.
13 July 1944:
At 1600, KOEI MARU departs Moji for Singapore with escort carrier SHINYO, light cruiser KASHII and kaibokan CHIBURI, SADO, CD-7 and CD-17 escorting convoy HI-69 consisting of tankers HAKKO, HARIMA, KUROSHIO, OMUROSAN, OTOWASAN, SERIA and TENEI MARUs and transports AKI, ASAMA, KACHIDOKI (ex-PRESIDENT HARRISON) KIMIKAWA, MANKO and SAIGON MARUs and escort carriers KAIYO and TAIYO, each loaded with aircraft for Luzon. SHINYO's aircraft conduct ASW patrols.
17 July 1944:
At 0600, off Takao, KOEI MARU is engaged in antisubmarine actions. Drops depth charges at N22.01N, 119.55E. That same day, MANKO MARU is detached.
18 July 1944:
Near Takao, Formosa. HARIMA MARU straggles from the convoy. About 0600, LtCdr John J. Flachsenhar's USS ROCK (SS-274) fires four torpedoes at HARIMA MARU, but misses.
At 0850, Cdr Alan Banister's USS SAWFISH (USS 276) fires nine torpedoes at the convoy at 21-58N, 119-50E. HARIMA MARU is hit by a single torpedo, but remains able to steam.
At 1055, LtCdr Roger M. Keithy's USS TILEFISH (SS-307) torpedoes and heavily damages CD-17 at 20-27N, 119-11E. The convoy continues to Manila without stopping at Takao as originally planned, but damaged HARIMA MARU and CD-17 put into Takao.
At 1830, KOEI MARU is again engaged in antisubmarine actions. Drops type 95 depth charges at N22-15N, 119-10E.
20 July 1944:
At 2100, convoy HI-69 arrives at Manila.
23 July 1944:
Loads food.
24 July 1944:
Loads heavy oil and mines. Lands depth charges.
25 July 1944:
Loads heavy oil and mine equipment.
26 July 1944:
Loads mines. Lands cargo.
3 August 1944:
San Miguel Bay, Philippines. KOEI MARU lays mines.
4-5 August 1944:
Lays mines in San Angles Gulf and departs.
7 August 1944:
Arrives at Takao, Formosa (Kaohsiung,Taiwan)
11 August 1944:
KOEI MARU departs Takao in an unnumbered convoy also consisting of minelayer SAIGON MARU escorted by subchaser CH-37.
15 August 1944:
Arrives at Arikawa Bay and later that day at Sasebo.
16 August 1944:
Departs Sasebo and later that day arrives at Mutsure.
17-18 August 1944:
Arrives at Moji. Loads rations and items for transport.
19 August 1944:
Departs Moji.
20 August 1944:
Arrives at Kure. Loads items for transport.
21 August 1944:
Departs Kure
22 August 1944:
Arrives at Sasebo.
23 August 1944:
Loads various items.
26 August 1944:
Lands rations, ammunition and depth charges. That same day, docked at Sasebo Navy Yard's No. 5 dock.
27 August 1944:
Undergoes repairs to the breech of her 120-mm cannon and Type 96 25-mm AA machine gun.
12 September 1944:
Undocked.
13 September 1944:
Departs Sasebo and arrives at Tamano. Undergoes hull and engine repairs and maintenance at Mitsui Engineering & Shipbuilding shipyard and fitting of new weapons including repairs to depth charge machinery.
11 September 1944:
Her compass is self-corrected and new machine guns are sighted.
12 September 1944:
Completes hull and engine repairs, maintenance and new weapons installation.
13 September 1944:
Arrives at Moji. Ties up at Hesaki anchorage:
13-14 September 1944:
Loads various items.
14 September 1944:
Loads raw food products.
15 September 1944:
Departs Moji and arrives at Sasebo.
16-17 September 1944:
Loads amphibious objects for transport .
18-20 September 1944:
Loads fresh water.
21 September 1944:
Loads heavy oil and mines.
23 September 1944:
Loads fresh water.
24 September 1944:
Loads rations.
25 September-8 October 1944:
Four type 96 single mount 25 mm machine guns and type 93 13-mm single mount machine guns are fitted.
11 October 1944:
Conducts a trial run, magnetic compass is adjusted and new machine guns are test-fired.
12 October 1944:
Completes hull repairs and new weapons fitting.
13 October 1944:
Arrives at Moji.
13-14 October 1944:
Loads various items.
14 October 1944:
Loads fresh provisions
15 October 1944:
Departs Moji and arrives at Sasebo.
16-17 October 1944:
Loads items for transport.
18-20 October 1944:
Loads fresh water.
21 October 1944:
Loads heavy oil supply and mines.
23 October 1944:
Loads fresh water.
24 October 1944:
Loads food.
25 October 1944:
Departs Sasebo and arrives at Ebisu Bay then returns to Sasebo.
31 October 1944:
Loads mines.
4 November 1944:
Loads 260 mines.
6 November 1944:
Departs Sasebo and arrives at Imari
8 November 1944:
Lands 260 mines.
11 November 1944:
Loads 150 tons of fresh water.
16 November 1944:
Loads food.
21 November 1944:
Anchors at Kaneshima
22 November 1944:
Departs Kaneshima.
23 November 1944:
Lays mines off Kaneshima
24 November 1944:
Arrives at Samchonpa, Korea, W of Pusan.
25 November 1944:
Arrives at Kabutoshima. Loads 50 tons of heavy oil.
26 November 1944:
Loads 260 mines and 220 tons of fresh water.
28 November 1944:
Departs Kabutoshima.
29 November 1944:
Arrives at Chinshimaoki, Korea.
30 November 1944:
Lays mines, then anchors at Kaneshima.
5 December 1944:
Arrives at Sasebo.
20 December 1944:
Loads 50 mines.
21 December 1944:
Loads 50 mines and food.
22 December 1944:
Loads mine accessories, machine bullets and medicine.
23-24 December 1944:
Undergoes fitting of machine gun equipment.
26 December 1944:
Loads 260 mines.
27 December 1944:
Loads 260 mines.
1 January 1945:
Departs Sasebo and arrives at Arikawa Bay.
2 January 1945:
Departs Arikawa Bay. Lays 230 mines off Tokai, S of Nagoya.
3 January 1945:
Arrives at Sasebo. Loads 290 mines.
5 January 1945:
Departs Sasebo and arrives at Arikawa Bay.
6 January 1945:
Departs Arikawa Bay. Later that day, engages in air action, then lays 290 mines off Tokai.
7 January 1945:
Arrives at Sasebo.
12 January 1945:
KOEI MARU receives a message requesting urgent transport of Type 93 mines and other items.
15 January 1945:
KOEI MARU receives a message to transport mines to the Okinawa area.
19 January 1945:
Departs Sasebo and arrives at Tomie, Goto-Retto.
22 January 1945:
Departs Tomie.
23 January 1945:
Arrives at Arikawa Bay.
25 January 1945:
Departs Arikawa Bay and arrives at Ebisu Bay
26 January 1945:
Departs Ebisu Bay.
27 January 1945:
Arrives at Naha, Okinawa.
28 January 1945:
Begins landing various objects. Minelayers SAISHU and NUWAJIMA come alongside and each receives 100 mines from KOEI MARU.
29 January 1945:
SAISHU receives another 100 mines while NUWAJIMA receives 80 more mines. KOEI MARU completes landing various objects. That same day, KOEI MARU receives a message from Sasebo to support the 40th “Shinyo” explosive motor boat (EMB) Squadron based on Okinawa and 44th EMB) Squadron based at Amami Oshima.
30 January 1945:
Departs Naha.
1 February 1945:
Arrives at Sasebo.
6 February 1945:
Departs Sasebo and arrives at Tomie.
8 February 1945:
Disembarks 187 explosive motor boat (EMB) Squadron members and lands 200 tons of equipment and aviation fuel in addition to 1,230 drums of oil.
13 February 1945:
Arrives at Sasebo.
20-24 February 1945:
Loads 500 mines.
25 February 1945:
Departs Sasebo and arrives at Ebisu Bay.
26 February 1945:
Departs Ebisu Bay.
27 February 1945:
Lays mines off Tokai.
1 March 1945:
Arrives at Sasebo. Loads various items.
2 March 1945:
Departs Sasebo and arrives at Ebisu Bay , then arrives at Sasebo and loads fresh water.
3-5 March 1945:
Loads food and explosive motor boat (EMB) weapon supplies. Loads 2,000 small-size mines. Loading. Departs Sasebo and arrives at Ebisu Bay .
8-10 March 1945:
Lands various items.
12 March 1945:
Arrives at Sasebo. Loads heavy oil.
15 March 1945:
Unloads gun powder and depth charges.
18-23 March 1945:
Moves to Sasebo Navy yard. Docked at No. 7 dock. Fitted with new active sonar devices. Four type 96 single mount 25 mm machine guns’ boresights undergo conversion and her single mount Type 93 13-mm machine gun stands are fitted with bulletproof sheet metal shields.
27 March 1945:
Undocked. Ties up at No. 1 quay.
29 March 1945:
Captain Takahashi leaves the ship. Cdr Nakagaki Yoshiyuki assumes command.
1 April 1945:
Undergoes magnetic compass adjustments. Moves to No. 3 quay
2 April 1945:
Loads depth charges and gun powder.
6 April 1945:
Departs Sasebo Navy Yard’s No. 3 quay and moves to Sasebo harbor.
7-8 April 1945:
Loads mines.
8 April 1945:
Loads fresh provisions.
9 April 1945:
Departs Sasebo and that day arrives at Imari.
10 April 1945:
Attached to the 18th Squadron, Seventh Fleet, Combined Fleet. Departs Imari and arrives at Mutsure Island
11 April 1945:
Arrives at Saeki. KOEI MARU is moored under camouflaged nets.
12 April 1945:
Saeki. Minelayers KATASHIMA, KUROKAMI, NUWAJIMA and SAISHU come alongside KOEI MARU and load mines transferred from her.
13 April 1945:
Loading operations are completed.
14 April 1945:
Departs Saeki. At 10.8 nms and 294 degrees off Himejima lighthouse, KOEI MARU strikes a mine and suffers slight rudder damage. Later, arrives at Mutsure Island
16 April 1945:
Lays mines in Tsushima Strait (Seisui road).
16-17 April 1945:
Arrives at Ebisu Bay
17 April 1945:
Departs Ebisu Bay
18 April 1945:
Arrives at Sasebo. Moves to Sasebo Navy Yard. Lands ammunition and enters No. 5 dock.
19 April 1945:
Undergoes of damage repairs.
23 April 1945:
Load assorted goods.
28 April 1945:
Undocked. Reloads ammunition and mines.
1 May 1945:
Cdr Nakagaki is promoted Captain. KOEI MARU departs Sasebo then arrives at Kogushi and departs.
2 May 1945:
Arrives at Saeki. KOEI MARU and NIIZAKI begin loading mines.
3 May 1945:
Loading operations on KOEI MARU are completed. Three tugboats and minelayers KUROKAMI and KATASHIMA come alongside and load mines
4 May 1945:
Departs Saeki and arrives at Nagashima. Loads mines and departs for Iwaishima.
6 May 1945:
Departs Iwaishima and arrives at Nagashima.
9 May 1945:
Loads raw food products.
11 May 1945:
Departs Nagashima and arrives at Sawakaminari then departs.
12 May 1945:
Arrives at Mutsure and then departs for Fukuoka Bay. Seven miles and 146 degree off Ubemisaki Light, KOEI MARU strikes a mine and suffers damage. Later, undergoes mine damage repairs at Sasebo Navy Yard’s No. 3 quay.
13 May 1945:
Arrives at Ebisu Bay and then Fukuoka Bay, departs and arrives at Tsushima Strait.
16-18 May 1945:
Sasebo Navy Yard. Undergoes engine repair work. Later, loads rations
18 May 1945:
Loads mines and 100 tons of heavy oil.
19 May 1945:
Departs Sasebo and arrives at Karatsu Bay.
21 May 1945:
Arrives at Imari Bay, departs and returns to Karatsu Bay. Later that same day, arrives at Tsushima Straits.
22 May 1945:
Arrives at Imari Bay and undergoes Squadron training. Later, ties up at Sasebo’s No. 2 quay.
23 May 1945:
Undergoes generator repairs.
24 May 1945:
Loads mines.
25 May 1945:
Loads rations.
27 May 1945:
Loads mines.
28 May 1945:
Loads more mines.
31 May 1945:
Arrives at Yobuko harbor. KOEI MARU supplies a cargo of mines to auxiliary minelayer EIJO MARU. Minelayer KYOSAI also loads mines.
1 June 1945:
Arrives at Tsushima Straits. The minelayers lay a minefield.
2 June 1945:
Arrives at Ominato and is placed under the Ominato Security Office.
25 June 1945:
Attached to the Seventh Fleet Annex, Combined Fleet:
14 July 1945:
Arrives at Wakkanai
21-23 July 1945:
Arrives at Ominato. Deploys mines in La Perouse Strait.
10 August 1945:
Carrier-based planes of Admiral (later Fleet Admiral) William F. Halsey Jr’s (USNA '04) Third Fleet’s fast carrier Task Force 38 attack shipping off Ominato. KOEI MARU is hit and damaged a 500-pound bomb.
15 August 1945:
Japan accepts the Allies “Potsdam Declaration” (of unconditional surrender) and hostilities cease. KOEI MARU is surrendered to the Allied Forces in battle-damaged condition.
August 1945: Designated an auxiliary transport ship under Yokosuka local demobilization station jurisdiction. Assigned SCAJAP No. K-125.
21 August 1945:
Arrives at Odomari.
23 August 1945:
Arrives at Ominato.
26 August 1945:
Former IJN Captain Sato Shigeyoshi is appointed Supervisor of KOEI MARU.
1 December 1945:
Removed from the Navy List.
1946-1947:
Repaired and attached to the Allied Repatriation Service and put in service to return former Imperial troops to the homeland. [2]
1947:
Returned to civilian ownership.
1950:
Sold to Daido Kaiun, K.K., Kobe.
4 May 1962–1963:
Sold for scrap.
1962-63
Broken up at Yokosuka.

Author's Notes:
[1] Greenwich (Kapingamarangi) Island is southernmost Island in the Carolines and is located about 500 nms SW of Truk. The Japanese fitted the island with a radio station, barracks and AA guns.
[2] Allied occupation forces were responsible for the return of six million Japanese military personnel and civilians from Japan's defunct far-flung Empire. In addition, there were over a million Korean and about 40,000 Chinese prisoners and conscript laborers and approximately 7,000 Formosans and 15,000 Ryukyu Islanders to be repatriated.
Some Allied and many former IJN warships, from aircraft carriers to kaibokan, were used to facilitate the enormous repatriation effort. Japanese vessels and crews were used to the fullest extent possible to conserve Allied manpower and accelerate demobilization. Each ex-IJN ship first had to be demilitarized; guns removed or, in the case of large warships, barrels severed, ammunition landed and, if fitted, radar and catapults removed.
Repatriation of the Chinese on Japanese ships began early in October from Hakata near Fukuoka, but U.S. guard detachments had to be placed on many ships to prevent disorder because the Japanese crews could not control the returnees.
Japanese-run repatriation centers were established at Kagoshima, Hario near Sasebo, and Hakata. Other reception centers were established and operated at Hakodate, Kure, Maizuru, Moji, Uraga, Sasebo, Senzaki, Shimonoseki and Yokohama. Allied line and medical personnel supervised the centers. Incoming Japanese were sprayed with DDT disinfectant, examined and inoculated for typhus and smallpox, provided with food and transported to their final destination in Japan.

-Bob Hackett

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