SOKAITEI!

© 2005-2007 Bob Hackett and Peter Cundall

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28 May 1938:
Tokyo. Laid down at the Ishikawajima shipyard.

18 February 1939:
Launched and numbered W-12.

15 August 1939:
Completed and registered in the IJN at the Sasebo Naval District.

1 June 1941:
W-12 is assigned to Vice Admiral Takahashi Ibo's (former CO of KIRISHIMA) Third Fleet's 1st Base Force in MineSweepDiv 21 with W-7, W-8, W-9, W-10 and W-11.

21 September 1941:
Cdr (Rear Admiral, posthumously) Kitamura Masayuki (45) assumes command of MineSweepDiv 21.

27 November 1941:
Departs Sasebo.

30 November 1941:
Arrives at Mako, Pescadores.

December 1941:
Lt Hanyu Hidekazu assumes command.

7 December 1941: Operation "M" - The Attack on the Southern Philippines:
W-12 departs Mako in Rear Admiral (later Vice Admiral) Nishimura Shoji’s Vigan Invasion Force.

17 December 1941:
Departs Amami O-Shima. Escorts convoys to Lamon Bay and Davao.

9 January 1942: Operation "H" - The Invasion of Celebes, Netherlands East Indies:
MineSweepDiv 21's W-12, W-7, W-8, W-9 and W-11, light cruiser NAGARA, patrol boats PB-1, PB-2, PB-34 and SubChasDiv 1's CH-1, CH-2 and CH-3 depart Davao escorting eight transports carrying Captain (later Vice Admiral) Mori Kunizo's (former CO of AO SATA) Sasebo No. 1 Combined Special Naval Landing Force (SNLF) and Rear Admiral Kubo's 1st Base Force.

11 January 1942: The Invasion of Menado, Celebes Dutch East Indies:
Rear Admiral Kubo’s 1st Base Force with MineSweepDiv 21, NAGARA, patrol boats and SubChasDiv 1’s CH-1, CH-2 and CH-3 provides escort for the Menado invasion force of eight transports carrying Captain Mori's Sasebo No. 1 Combined SNLF.

At 0300, the SNLF lands on Kema, Celebes. At 0400, they land on Menado. Later, 334 men of Cdr (later Captain) Horiuchi Toyoaki's (later XO of TAKAO) Yokosuka No. 1 SNLF (Air) are dropped successfully from Mitsubishi G3M1-L "Nell" converted transport aircraft in the Menado-Kema area. The paratroops seize Langoan airfield.

21 January 1942:
Escorts the Kendari invasion convoy and conducts minesweeping.

23-24 January 1942: The Invasion of Kendari, Celebes:
MineSweepDiv 21’s W-12, W-7, W-8, W-9 and W-11, DesRon 10’s light cruiser NAGARA, DesDiv 15’s HAYASHIO, KUROSHIO, OYASHIO and NATSUSHIO, DesDiv 16’s TOKITSUKAZE, HATSUKAZE, AMATSUKAZE and YUKIKAZE, and Subchaser Div 1’s CH-1 and CH-2 escort Rear Admiral Kubo’s Kendari Invasion Force under consisting of six troop transports carrying Captain (later Vice Admiral) Mori Kunizo’s Sasebo Combined Special Naval Landing Force (SNLF). The 11th Seaplane Tender Division’s CHITOSE and MIZUHO provide distant support.

29 January 1942:
Departs Kendari. Escorts the Ambon, invasion convoy.

31 January 1942: The Invasion of Ambon Island, Moluccas, Netherlands East Indies:
The convoy includes ten transports carrying 820 men of Rear Admiral (later Vice Admiral) Hatakeyama Koichiro's (former CO of KINUGASA) Kure No. 1 SNLF, elements of the Sasebo SNLF and the 228th Infantry Regiment escorted by Rear Admiral Tanaka's DesRon 2’s light cruiser JINTSU, DesDiv 8’s ASASHIO, MICHISHIO, ARASHIO and OSHIO, DesDiv 15’s HAYASHIO, KUROSHIO, OYASHIO and NATSUSHIO, DesDiv 16’s TOKITSUKAZE, HATSUKAZE, AMATSUKAZE and YUKIKAZE, Minesweeper Div 21’s W-7, W-8, W-9, W-11 and W-12 and Subchaser Div 1’s CH-1, CH-2 and CH-3. CHITOSE and MIZUHO arrive at Ceram and provide air cover for the invasion convoy.

2 February 1942:
Ambon. W-12 explodes a mine while sweeping and is damaged.

10 March 1942:
Assigned to the 2nd Southern Expeditionary Fleet’s 21st Special Base Force.

20 April 1942:
Departs Ambon. Escorts convoys.

24 April 1942:
Arrives at Surabaya, Java. Escorts convoys

8 March 1942: Operation "S" – The Seizure of the Lesser Sunda Islands:
At 0900, W-12, CruDiv's 16 light cruiser IZUSU, torpedo boat TOMOZURU and subchasers CH-6, CH-19 and CH-20 depart Surabaya for Lombok Island escorting Rear Admiral Hara Kenzaburo’s Lesser Sunda Islands Invasion Force consisting of seaplane tender SANYO MARU and minelayer WAKATAKA carrying the Yokosuka No. 1 SNLF and two Army transports.

9 May 1942:
At 1700, the invasion convoy arrives at Mataram, Lombok Island. The SNLF lands and occupies the island.

10 May 1942:
Departs Mataram.

13 May 1942:
At 0830, arrives at Bima, Soembawa Island. The SNLF lands and occupies Bima. At 1000, departs Bima.

14 May 1942:
Arrives at Reo, Flores Island. The SNLF lands and occupies Reo.

16 May 1942:
Arrives at Labuhanbadjo, Flores Island and at Waingapoe, Soemba Island. The SNLF lands and occupies both locations.

17 May 1942:
Arrives at Larantoeka and Endeh, Flores Island. The SNLF lands and occupies both locations.

12 August 1942:
Arrives at Surabaya. Drydocked for hull repairs.

26 August 1942:
Departs Surabaya. Escorts a convoy.

6 September 1942:
Arrives at Manila.

16 September 1942:
Arrives at Sasebo. Drydocked.

24 October 1942:
Undocked.

29 October 1942:
Departs Sasebo.

14 November 1942:
Arrives at Surabaya.

16 November 1942:
Surabaya. Sweeps the Kohoku waterway for mines. Escorts convoys.

8 December 1942:
Departs Surabaya. Escorts a convoy to Ambon.

April 1943:
Lt Kawano Osamu assumes command.

2 June 1943:
Escorts convoys to western New Guinea.

1 August 1943:
Arrives at Surabaya. Drydocked.

13 August 1943:
Undocked.

15 August 1943:
Departs Surabaya. Escorts a convoy to Ambon.

10 November 1943:
Departs Balikpapan escorting SENKO MARU.

E 12 November 1943:
W-12 hands over escort to W-8 at 04-00S, 112-00E and heads for Surabaya. SENKO MARU and W-8 proceed to Padang.

16 November 1943:
At 1600, departs Surabaya escorting NANKAI MARU.

17 November 1943:
W-12 develops engine trouble. The convoy anchors for five hours at Kabanramari Island, Postiljon Archipelago, while W-12 carries out engine repairs.

20 November 1943:
At 0730, arrives at Ambon. W-12 is detached from the convoy that proceeds to Halmahera Island,.

26 November 1943:
After 1200, W-12 and W-11 depart Ambon escorting a convoy consisting of SUEZ MARU carrying sick and wounded Japanese troops and 1,102 mostly sick British and Dutch POW's. A E-13A1 "Jake"float plane is located on the fore deck of the ship. The aircraft has a fractured fuselage and is scheduled for repairs at Repair Depot No. 102 in Surabaya.

27 November 1943:
W-11 detaches from the convoy and heads for Kendari.

28 November 1943:
In the evening, W-12 detaches to hunt an enemy submarine, but rejoins SUEZ MARU the following morning.

29 November 1943:
At 0800, LtCdr Thomas W. Hogan's USS BONEFISH (SS-223) fires four torpedoes at the overlapping targets of SUEZ MARU and W-12 at 06-22N, 116-35E. SUEZ MARU's lookouts sight the torpedoes and she avoids two. The third explodes prematurely, but Hogan's fourth torpedo strikes hold No. 4, which along with hold No. 3 contains the POW's. Most of the POW's in the hold are killed in the blast. The ship settles rapidly with a steep list and sinks at 0940.

About 200-250 POW's survive. W-12 rescues about 200-250 Japanese and Koreans, but is unable to accommodate any POW's. After much arguing, and on the insistence of Lt Kawano Usumu, CO of W-12, IJA Lt Koshio Masaji, in charge of the POW's, agrees to massacre the survivors in the water. Between 1415 and 1630, a rifle party of a dozen men is based on the warship's foredeck and together with a machine gun mounted on the bow opens fire on the POW's. Either in the ensuing massacre, or in the water over the next few days, all the POW's are killed.

E 1 December 1943:
W-12 is diverted to Batavia because of mines in Surabaya.

1 March 1944:
At 1200, W-12 and auxiliary subchaser CHa-103 depart Surabaya escorting a convoy consisting of KITA MARU and tankers KYOEI MARU and TSURUMI.

2 March 1944:
A radio message is received advising Balikpapan Port has been mined. The convoys sails to Pagatan arriving there later that day.

3 March 1944:
At 0400, departs Pagatan. At 0930, KITA MARU is detached from the convoy. Later that day, the convoy arrives in the Kotabaru Sea and anchors there.

4 March 1944:
At 1530, departs Kotabaru Sea and at 2000 arrives at Pamukan Bay.

5 March 1944:
At 0500, departs Pamukan Bay and later that day arrives at Balikpapan.

26 March 1944:
At 0800, W-12 and subchaser CH-2 depart Surabaya escorting a convoy consisting of NICHINAN, HEIAN and KUNIYAMA MARUs. That evening, anchors at Kangean Island.

27 March 1944:
At 0600, departs Kangean Island. At 1000, LtCdr Willard R. Laughon's USS RASHER (SS-269) torpedoes and sinks NICHINAN MARU at 07-27S 115-52E. W-12 and subchaser CH-2 counter-attack dropping 35 depth-charges without effect. The convoy returns to Surabaya. At 1825, the convoy again departs port.

28 March 1944:
The escort is handed over to patrol boat No.104 at 07-15S, 115.50E. W-12 and subchaser CH-2 return to Surabaya.

12 April 1944:
At 1300, W-12 and subchaser CH-2 depart Surabaya escorting a convoy consisting of MIKASA MARU and SHINSEI MARU No. 17.

15 April 1944:
Arrives at Bima Bay, Sumbawa Island.

16 April 1944:
At 0500 departs Bima Bay.

17 April 1944:
Arrives at Maumere, Flores Island.

18 April 1944:
Departs Maumere.

19 April 1944:
At 1930, arrives at Bima Bay.

22 April 1944:
At 0130, departs Bima Bay.

23 April 1944:
At 1200, arrives at Surabaya.

7 May 1944:
Arrives at Surabaya. Drydocked.

25 May 1944:
Undocked.

3 June 1944:
At 0900, W-12 departs Surabaya escorting a convoy to Balikpapan, Borneo consisting of KITA, ENOSHIMA and JAMBI MARUs.

10 June 1944:
At 1000, W-12 departs Surabaya escorting a convoy consisting of IKUTAGAWA, and SEIA MARUs.

11 June 1944:
At 2030, arrives at Laut Island, SE Borneo.

12 June 1944:
At midnight, departs Laut Island. At 1920, arrives at Doangdoangan Island. At 2100, auxiliary subchaser SHONAN MARU No. 1 joins the convoy.

13 June 1944:
At midnight, departs Doangdoangan Island. At 1845, arrives at Tioro Strait.

14 June 1944:
At 0910 departs Tioro Straits and SHONAN MARU No. 1 is detached. At 1800, enters Wowoni Channel.

15 June 1944:
At 0500, departs Wowoni Channel. At 1730, arrives at Litrusaru.

16 June 1944:
At 0900, departs Litrusaru. At 1730 arrives at the N side of Sanana Island.

17 June 1944:
At 0230 departs Sanana Is. At 1630, arrives at Namlea, Buru Island.

18 June 1944:
At 0600, departs Namlea and at 1340, arrives at Ambon.

24 June 1944:
At 0700, W-12, torpedo boat KIJI, auxiliary minesweeper Wa-9 and auxiliary NITTO MARU No. 18 depart Ambon escorting a convoy consisting of SHINNO and KOHOKU MARUs and TENKAI No. 4. At 1720, arrives at Namrole, Buru Island.

25 June 1944:
At 0530, departs Namrole. W-12 and TENKAI No. 4 are detached and head for Surabaya.

E 27 June 1944:
Arrives at Surabaya.

30 June 1944:
At 1100, W-12, torpedo boat KARI and auxiliary minelayer SHONAN MARU No. 2 depart Ambon escorting a convoy to Surabaya consisting of IKUTAGAWA, and SEIA MARUs and LSTs 101 and 102.

7 July 1944:
W-12 drops depth charges on a suspected submarine without results.

9 July 1944:
Arrives at Surabaya.

4 August 1944:
At 1330, W-12 and subchasers CH-26, CH-34 and CH-35 depart Ambon escorting a convoy to Staring Bay, Celebes consisting of SHINTAI, KANTO and KURAMASAN MARUs.

5 August 1944:
CH-26 reverses course back to Ambon.

6 August 1944:
At 1400, the convoy arrives at Staring Bay.

October 1944:
An unknown officer assumes command.

17 October 1944:
At 0650, W-12 departs Bandjarmasin, S Borneo, escorting a convoy consisting of KANTO, TENCHO and DAI MARUs. At 1320, a report of an enemy submarine ahead is received and the convoy turns back to Batakani, near Cape Selatan arriving there at 1930.

18 October 1944:
At 2100, departs Batakani.

20 October 1944:
At 1530, arrives at Surabaya.

16 November 1944:
At 0830, W-12, auxiliary subchasers CHa-2 and CHa-3 depart Sebuku Island, SE Borneo escorting a convoy consisting of AKITSU MARU towing HOKKAI MARU assisted by BAKUKO MARU and cargo ship SHUNSEN MARU.

18 November 1944:
At 2345, arrives in the swept eastern channel to Surabaya Port.

19 November 1944:
At 1530, arrives at Surabaya. HOKKAI MARU enters drydock.

14 February 1945:
At 0600, W-12 and patrol boat No. 10 depart Bandjarmasin escorting convoy BASU-12 consisting of DAI, OTOME, KOMPIRA, NITTEI, HEIYO, TOKUYAMA and NANSHO MARUs, communications boats No's 312, 401, 402, 408 and 409. At 1300, No. 408 breaks down and No. 409 takes the boat in tow back to Bandjarmasin.

15 February 1945:
At 2020, the convoy anchors in Surabaya's eastern channel.

16 February 1945:
At 0800, departs and at 1100, arrives at Surabaya Port.

2 April 1945:
Departs Surabaya. Performs transport duty to Timor Island.

4 April 1945:
W-12 and W-34 and torpedo boat KARI depart Surabaya escorting light cruiser ISUZU transporting an army detachment from Kupang to Sumbawa Island. The ISUZU group is sighted off Paternoster Island by a wolf pack led by Cdr (later Rear Admiral) Francis D. Boyle's CHARR (SS-328) with LtCdr Herman E. Miller's USS BESUGO (SS-32l) and LtCdr William B. Parham's GABILAN (SS-252), but Japanese aircraft force the pack to dive and they are unable to attack.

6 April 1945:
Boyle's wolf pack is alerted about the position of the Japanese ships by an "Ultra" signals-intelligence message from ComSubPac at Pearl and takes up position near Bima Bay. They are joined there by ComSubSoWestPac's British submarine HMS SPARK.

Kupang Harbor. At dawn, ISUZU embarks an army detachment and departs for Sumbawa. N of Sumbawa, ISUZU is attacked by ten B-25 "Mitchell" bombers of the Dutch 18th Squadron based at Batchelor airfield S of Darwin, Australia. ISUZU is slightly damaged by near-misses. Later, she lands troops at Bima Bay, on the NE coast of Sumbawa.

Near Flores Island, Netherlands East Indies. ISUZU is hit in the bow by bombs from Consolidated B-24J "Liberator" bombers of the RAAF's No. 21 and No. 24 Squadrons based in Northern Australia. Two B-24's are shot down by Japanese aircraft.

Sape Strait, between Sumbawa and Komodo islands. About 1600, Miller's BESUGO fires nine torpedoes at the ISUZU group. They miss ISUZU, but two hit W-12 that has a deckload of troops. W-12 is beached, but torpedoed again and sinks at 08-13S, 119-14E.

25 May 1945:
Removed from the Navy List.

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Authors Note:
Thanks go to Mr. Aki of Japan and Matthew Jones of Ohio for help in identifying COs.

-Bob Hackett and Peter Cundall.

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