SOKAITEI!

© 2005-2007 Bob Hackett and Peter Cundall

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6 April 1933:
Osaka. Laid down at the Fujinagata Zosen shipyard.

14 February 1934:
Launched and numbered W-15.

21 August 1934:
Completed and registered in the Kure Naval District.

1 December 1936:
LtCdr Ikeda Akira assumes command.

10 June 1941:
Takao, Formosa. Assigned to Rear Admiral (later Vice Admiral) Hirose Sueto's (former CO of AOBA) 2nd Base Force of Vice Admiral Takahashi Ibo's (36) (former CO of KIRISHIMA) Third Fleet.

1 December 1941:
Departs Sasebo.

4 December 1941:
Arrives at Mako, Pescadores.

7 December 1941: Operation "M" -The Attack on the Philippines:
Escorts a convoy and sweeps mines for the Aparri, Philippines invasion force.

17 December 1941:
Departs Takao. Escorts the invasion convoy to Lingayen Gulf.

22 December 1941:
Arrives at Lingayen Gulf. Conducts mine sweeping.

31 December 1941:
Departs Takao escorting a convoy.

5 January 1942:
Arrives at Davao, Philippines.

7 January 1942: The Invasion of Dutch Borneo:
Rear Admiral Hirose’s Tarakan Occupation Force departs Davao. Hirose's force include MineSweepDiv 11’s W-15, W-13, W-14, W-16, MineSweepDiv 30’s W-17and W-18, SubChasDiv 31’s CH-10, CH-11 and CH-12, patrol boats PB-36, PB-37 and PB-38 and other auxiliary ships.

The Tarakan invasion convoy includes Army transports TSURUGA, LIVERPOOL, HAVANA, KURETAKE, NICHIAI, HITERU, TEIRYU, HANKOW and EHIME MARUs carrying MajGen Sakaguchi Shizuo’s 56th Mixed Infantry Group and the Kure No. 2 Special Naval Landing Force (SNLF) and Navy transports KUNIKAWA, KANO, KAGU, KOKUYO and RAKUTO MARUs. The convoy’s escort is provided by Rear Admiral (later Vice Admiral) Nishimura Shoji’s DesRon 4’s light cruiser NAKA with DesDiv 2’s HARUSAME, SAMIDARE, YUDACHI and MURUSAME, DesDiv 9’s ASAGUMO and MINEGUMO, NATSUGUMO and DesDiv 24’s UMIKAZE, KAWASKAZE, YAMAKAZE and SUZUKAZE. The 21st Air Flotilla’s tenders SANUKI and SANYO MARUs provide air cover.

10 January 1942:
Arrives at Tarakan. Conducts mine sweeping and patrols the peripheral sea area.

11 January 1942:
Rear Admiral Hirose's Force invades Tarakan, Borneo.

21 January 1942: The Invasion of Balikpapan, Borneo.
W-15, W-16, W-17 and W-18 depart Tarakan with the No. 2 Base Force's subchasers CH-10, CH-11 and CH-12 and patrol boats PB-36, PB-37 and PB-38 scorting the Balikpapan Invasion Convoy consisting of 16 transports carrying the Sakaguchi Brigade and the Kure No. 2 SNLF. DesRon 4 provides additional escort. Cover is provided by NAKA with DesDiv 2's YUDACHI, SAMIDARE, HARUSAME, DesDiv 9's ASAGUMO, MURASAME, MINEGUMO, NATSUGUMO and DesDiv 24's KAWAKAZE, YAMAKAZE and UMIKAZE. The 21st Air Flotilla again provides air cover.

Air reconnaissance by the ABDA (American-British-Dutch-Australian) forces is hampered by poor weather, but ABDA Air finally locates the IJN invasion force. The ABDA deploys the submarines USS S-40, PORPOISE (SS-172), PICKEREL (SS-177), STURGEON (SS-187), SAURY (SS-189) and the SPEARFISH (SS-190) and Dutch submarines K-XIV and K-XVIII to intercept the IJN force.

Timor, Kupang Bay. Rear Admiral (later Vice Admiral) William A. Glassford's Task Force 5's light cruisers USS MARBLEHEAD (CL-12), BOISE (CL-47) and Cdr Paul H. Talbot's DesDiv 59's old flush deck, four stack destroyers PARROTT (DD-218), POPE (DD-225), JOHN D. FORD (DD-228) and PAUL JONES (DD-230) are ordered by the Admiral (later Senator) Thomas C. Hart, ADBAFLOAT Commander, to intercept the convoy before it reaches Balikpapan. Glassford heads north to find the IJN invasion force but BOISE runs aground on an uncharted reef in the Sape Strait. She is forced to retire for repairs. Then MARBLEHEAD develops engine trouble and can make no more than 15 knots. DesDiv 59 is detached and increases speed to 27 knots so as to arrive at Balikpapan at midnight on January 23rd.

23 January 1942:
Storms protect the invasion force until it is almost to Balikpapan, Borneo. At 1525, nine Dutch Martin B-10 bombers from Samarinda attack and hit two of the transports, the 7,070-ton TATSUGAMI MARU and 6,557-ton NANA MARU that has to be abandoned and later sinks. TATSUGAMI MARU continues on to Balikpapan. At 2130, the transports begin disembarking their troops.

24 January 1942:
Dutch Navy LtCdr C. A. J. van Well Groeneveld's (former CO of K-XIV) submarine K-XVIII, operating on the surface due to the weather, fires four bow torpedoes at NAKA, but they all miss. At 0045, Groeneveld attacks and sinks 6,987-ton transport TSURAGA MARU at 00-10N, 118-0E. Nishimura moves his covering force eastwards to carry out antisubmarine sweeps.Talbot's DesDiv 59 arrives from the south. Since Nishimura's covering forces are now to the east searching for submarines, the four destroyers are virtually unopposed.

At about 0245, PARROTT fires eight torpedoes at W-15 that she mistakes for a destroyer or cruiser. FORD also fires a torpedo at W-15 again. All miss or fail to explode. At 0316, they begin their first attack firing their 4-inch guns and launching ten torpedoes at the anchored transports, but all the torpedoes miss. Cdr Talbot orders another attack. At 0330, POPE hits and sinks 3,519-ton transport SUMANOURA MARU. At 0335, PARROTT and PAUL JONES sink already damaged transport TATSUGAMI MARU with torpedoes. At 0345, FORD sinks the 5,175-ton transport KURETAKE MARU with gunfire and torpedoes. Two other transports suffer damage from gunfire and torpedoes but remain afloat. POPE and PARROTT sink the 2nd Base Force's patrol boat PB-37 with torpedoes and gunfire. At 0350, their torpedoes gone, DesDiv 59 departs southward. At 0300, the Japanese begin landing troops at Balikpapan and, by dawn, they occupy the airfield. That same day, troops invade Kendari, Celebes.

24 February 1942: Operation "J" - The Invasion of Java, Netherlands East Indies:
W-15 escorts a convoy and sweeps mines in support of the Java campaign.

10 March 1942:
Assigned to Vice Admiral (later Admiral) Takasu Shiro's (former CO of ISUZU) 2nd Southern Expeditionary Fleet’s 22nd Special Base Force based at Balikpapan.

24 March 1942:
Borneo. Escorts convoys.

1 July 1942:
Arrives at Singapore. Undergoes repairs.

24 July 1942:
Departs Singapore for Balikpapan. Thereafter, escorts convoys from Balikpapan.

29 September 1942:
Departs Balikpapan.

10 October 1942:
Arrives at Rabaul.

23 October 1942:
Escorts a convoy from Shortland Islands, Bougainville.

6 November 1942:
At 1400, W-15, minelayer SHIRATAKA, torpedo boat HIYODORI and subchaser CH-16 depart Rabaul for Shortland escorting an unnumbered convoy consisting of ARIZONA, TOYO, NAGARA, YAMAZUKI, TEIYO, YUROI, TOYOKUNI, OIGAWA and SHINANOGAWA MARUs.

8 November 1942:
At 1020, the convoy arrives at Shortland.

4 March 1943:
At 0730, W-15 departs Truk for Rabaul escorting an unnumbered convoy consisting of ZUIKO and KIKUKAWA MARUs.

6 March 1943:
At 0500, the convoy arrives at Rabaul.

9 March 1943:
At 1600, W-15 departs Truk for Rabaul escorting an unnumbered convoy consisting of MIYODOMO, UJGAWA AND TAIKO MARUs.

11 March 1943:
At 0800, the convoy arrives at Shortland.

15 March 1943:
Reassigned to Captain (later Rear Admiral) Itagaki Akira's 1st Base Force, 8th fleet at Buin.

14 April 1943:
Hawaii. Fleet Radio Unit Pacific Fleet (FRUPAC) and two other stations of U.S.N. intelligence, code-named "Magic", intercept and decrypt a Japanese Naval Cipher JN-25D report of a planned inspection tour by Admiral Yamamoto Isoroku, C-in-C, Combined Fleet, throughout the South Pacific. Yamamoto will fly from Rabaul to Ballale Airfield, near Bougainville. According to the decrypt, on 18 April, Yamamoto and his staff will fly in two Mitsubishi G4M Bettys of the 205th Naval Air Group (NAG), escorted by six Mitsubishi A6M Zeke fighters of the 204th NAG, to depart Rabaul at 0600 and arrive at Ballale at 0800 (JST).

18 April 1943:
Easter Sunday. At 0710 (local D/T), 16 P-38 “Lightning” long-range fighter aircraft of the USAAF’s 339th Fighter Squadron under Major (later Colonel) John W. Mitchell take off from Henderson Field, Guadalcanal to ambush Yamamoto in the air as authorized by Admiral Chester Nimitz and President Roosevelt. At 0610 (JST), Yamamoto’s G4M departs Lakunai airfield at Rabaul, New Britain. Near Kahili, Bougainville, Yamamoto’s plane is shot down by a P-38. In the attack, Yamamoto is hit by machine-gun bullets and KIA. A second GM4 carrying Yamamoto's Chief of Staff, Vice Admiral Ugaki Matome (former CO of HYUGA) is also shot down by a P-38, but Ugaki survives.[1]

That same day, W-15 departs Buin for Ballale to rescue Yamamoto.

20 April 1943:
W-15 embarks the bodies of Admiral Yamamoto and ten other members of his party. The bodies are placed under a tent erected in the fore part of ship. At about 1600, W-15 departs Ballale for Buin. At Buin, an official autopsy of Yamamoto is conducted by LtCdr Tabuchi Jisaburo, Chief Medical Officer, 1st Base Force. Later that day, the remains are cremated by members of the Sasebo SNLF stationed at Buin. Yamamoto’s and the others' ashes are flown to Rabaul, then by flying boat to Truk where they are placed aboard battleship MUSASHI for return to Tokyo.

21 April 1943:
Escorts a convoy from Buin.

10 May 1943:
At 1500, W-15 departs Shortland escorting a convoy consisting of KASHI, SHINYU and SANWA MARUs and NISSEN MARU No. 5 and KOSHU MARU No. 2

12 May 1943:
At 0800, arrives at Rabaul.

17 May 1943:
At 1800, W-15 departs Rabaul for Shortland, Bougainville escorting a convoy consisting of ATSU and HEIWA MARUs and KOSOKU MARU No. 3.

19 May 1943:
At 0920, arrives at Shortland.

22 June 1943:
At 1300, W-15 departs Rabaul for Shortland escorting a convoy consisting of GIYU, UJIGAWA, KYOSEI, TAKUEI and KARIMO MARUs.

24 June 1943:
At 0830, arrives at Shortland.

18 July 1943:
Buin, Bougainville, Solomons. USN VB-11 and USMC VMSB-132 "Dauntless" SBD dive-bombers and USN VT-11 and VT-21 "Avenger" TBF torpedo-bombers escorted by USMC VMF 122, VMF 211 and VMF 221 F4U "Corsair" fighters and USAAF B-24 "Liberator" heavy bombers escorted by USAAF P-39 "Airacobra" and P-40 "Warhawk" fighters and RNZAF P-40s attack shipping in the Buin-Kahili area. They sink destroyer HATSUYUKI and damage destroyers HATSUKAZE and YUNAGI and W-15 in the attack. Later, W-22 tows W-15 to Rabaul.

7 August 1943:
Departs Rabaul accompaning the fleet.

28 August 1943:
Arrives at Kure.

1 September 1943:
Undergoes repairs for eight days.

October 1943:
Lt Niwa Eitaro assumes command.

25 November 1943:
Assigned to the Sasebo Guard Unit.

7 December 1943:
W-15 departs Sasebo for Shanghai escorting convoy SHI-704 consisting of RYOKA, NIKKIN and HOKUJU MARUs and DAIUN MARU No. 2. At 1400, the convoy runs into heavy weather. DAIUN MARU No. 2 returns to port.

8 December 1943:
At 1430, W-15 orders the other ships to also return to port because of the bad weather.

9 December 1943:
At 1655, in better weather, W-15, RYOKA and NIKKIN MARUs depart Sasebo. At some point in the journey, W-15 detaches and returns to Sasebo.

20 December 1943:
At 0300, the convoy arrives at Shanghai.

24 December 1943:
At 1730, W-15 departs Sasebo for Shanghai escorting convoy SHI-403 consisting of KOKKA, YUZAN, MIIKESAN, SHOKEI, and HOKUJU MARUs and BANSHU MARU No. 32.

24 December 1943:
At 1315, the convoy arrives at Shanghai.

30 December 1943:
At 1520, W-15 departs Shanghai escorting convoy MO-006 consisting of NARUTO, WAZAN, NISHO, MISHIMA, KORYU and KAMIKAZE MARUs.

3 January 1944:
At 0855, arrives at Sasebo.

1 February 1944:
At 1150, W-15 departs Shanghai escorting convoy MO-106 consisting of NARUO, MALAY, UGA, MUNEKATA, AOKI and WAKAMATSU MARUs. Shortly after leaving, high winds cause the convoy to lose formation

3 February 1944:
At 1715, the ships began reassembling near Mokpo.

4 February 1944:
At 0140, NARUO and UGA MARUs depart. The others follow later that day.

5 February 1944:
At 1005, arrives at Sasebo.

8 February 1944:
At 0720, W-15 departs Sasebo escorting convoy SHI-802 consisting of UNZEN and KITSURIN MARUs.

10 February 1944:
At 1750, at arrives Shanghai.

13 February 1944:
At 1250, W-15 departs Shanghai escorting convoy MONA-302 consisting of UNZEN and KITSURIN MARUs.

16 February 1944:
At 1605, arrives at Sasebo. Probably undergoes repairs and upkeep.

10 April 1944:
Assigned to the Sasebo Naval District's 4th Surface Escort Division.

17 April 1944:
Departs Sasebo escorting a convoy to Okinawa.

17 June 1944:
Departs Takao escorting a convoy to Manila.

30 August 1944:
Departs Sasebo escorting a convoy to Formosa.

7 September 1944:
W-15 departs Kagoshima with kaibokan CD-30, minelayers NUWAJIMA, NIIZAKI and auxiliary minesweepers TAKUNAN MARU No. 3, CHITOSE MARU and auxiliary CHOUN MARU No. 13 escorting convoy KATA-719 consisting of CHOSAN, EKISAN, AITOKU, SAKISHIMA, DAITOKU, TAIHAKU and NAKAGAWA MARUs and 18 other unidentified MARUs.

9 September 1944:
At 1000, arrives at Naha. Part of the convoy is detached.

15 September 1944:
Arrives at Kirun, Formosa.

October 1944:
Lt Morisawa Ikuo assumes command.

21 October 1944:
At 1200, W-15 departs Kagoshima with torpedo boat MANAZURU, kaibokan CD-30, subchaser CH-49, storeship KINEZAKI, auxiliary minesweeper SHONAN MARU No. 16 and auxiliaries KIKU MARU No. 7 and HIMESHIMA MARU escorting convoy KATA-916 consisting of MUROTO, CHOJUSAN, TOMITSU, EDOGAWA, BANSEI, TENSHO, AMAKUSA, SSHINTON, SANKA, SANJIN, HAKKA, HAYAMA, TORAI, TAIKYU, SAKISHIMA, RYUKYU, KANKYO and AMOY MARUs.

22 October 1944:
At 0730, LtCdr (later Vice Admiral) Veron L. Lowrance's US SEA DOG (SS-401) torpedoes and sinks storeship MUROTO and damages TOMITSU MARU at 29-18N, 129-44. ETORAI MARU takes TOMITSU Maru in tow. The convoy then shelters in Kasari Bay, Amami Oshima.

25 October 1944:
At 1230, arrives at Naha.

3 November 1944:
W-15 and W-16 depart Kagoshima with torpedo boat MANAZURU, auxiliary minesweeper SEKI MARU and SHONAN MARU No. 16 escorting convoy KATA-322 consisting of KAIRYU, KINZAN, KEIUN, KENJO, SEIZAN, TAISEI, TOSHO, GINZAN and MALAY MARUs and TAMON MARU No.12.

6 November 1944:
Arrives at Naha. Part of the convoy detaches and remains there.

20 November 1944:
At 1500, arrives at Kirun.

22 November 1944:
At 0730, W-15 departs Kirun with torpedo boat MANAZURU, auxiliary minesweeper SEKI MARU and SHONAN MARU No. 16 escorting convoy TAKA-206 consisting of DAIKIN, HOZAN, SANJIN, AMAKUSA, SAKAE and EIKAI MARUs.

At 2237, MANAZURU attacks a surfaced submarine at 24-45N, 122-32E. At 2330, LtCdr Anton R. Gallaher's USS BANG (SS-385) torpedoes and sinks AMAKUSA, HOZAN and SAKAE MARUs at 24-21N, 122-38E. [2]

27 November 1944:
At 2000, arrives at Naha.

1 March 1945:
At 0800, W-15 and W-17 depart Mutsure for Keelung with kaibokans IKUNA, CD-26 and CD-41 and subchaser CH-19 escorting convoy MOTA-40 consisting of IKOMASAN, AIZAN, DAIKI, TOYOGAWA, KITAKATA, ANKO and DOSHI MARUs. [3]

5 March 1945:
Off Akuke Jima, Ryukyu Islands. At 1042, LtCdr Walter F. Schlech's USS TILEFISH (SS-307) torpedoes and damages W-15's stern at 29-36N, 129-45E. W-15 is beached on the shoal island of Suwasi with assistance from BANSHU MARU No. 51 to facilitate her salvage. Schlech fires two more torpedoes at W-15, but they explode on the reef. W-15 is abandoned and later deemed a constructive total loss.

10 May 1945:
Removed from the Navy List.

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Authors' Notes:
[1] Controversy surrounded the claims of who actually shot down Yamamoto. The late Captain (later Colonel, AFRes) Thomas G. Lanphier and Lt (later Colonel) Rex T. Barber both claimed credit. After reviewing the mission in 1960 and again in 1985, the U. S. Air Force officially shared the kill between the two pilots.

[2] Some sources credit LtCdr Louis D. McGregor's USS REDFISH (SS-395) with sinking AMAKUSA MARU.

[3] Some sources indicate that W-15 was part of the escort of MOTA-40, but others do not.

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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