W-21 (W-19 class) scanned from Gakken, V. 45
IJN Minesweeper W-34:
Tabular Record of Movement
© 2008-2015 Bob Hackett and Peter Cundall
Tokyo. Laid down at Ishikawajima Zosensho K.K. as minesweeper No. 419.
Launched and numbered W-34.
29 May 1944:
Completed and registered in the IJN. Reserve Lt Komori Toru is the Commanding Officer.
3 June 1944:
At 0640, departs Yokosuka and at 2050 anchors off Matoya.
4 June 1944:
At 0500, departs Matoya. At 1730, arrives at Wakanoura.
5 June 1944:
At 0415, departs Wakanoura. At 1740, arrives at Kure.
11 June 1944:
At 0800, departs Kure. At 1800 arrives at Saiki.
22 June 1944:
At 0640, departs Saiki on patrol off Bungo Suido. At 2120 arrives at Saiki.
27 June 1944:
At 0420 departs Saiki. At 1845 arrives at Uzuki Bay.
28 June 1945:
At 0630 departs Uzuki Wan. At 1200, arrives at Saiki.
1 July 1944:
W-34 is assigned to the 10th Special Base Force of the Southwest Area Fleet's First Southern Expeditionary Fleet and based at Singapore, Malaya.
2 July 1944:
At 0645, departs Saiki. At 1930, arrives at Kure.
4 July 1944:
At 1945, departs Kure.
5 July 1944:
At 1220, arrives at Miike.
6 July 1944:
At 1245, W-34 departs Miike, Kyushu for Takao, Formosa with destroyer HATSUSHIMO, kaibokan CD-1 and CD-22 escorting convoy MOMA-02 consisting of SEATTLE, SHOZAN, JINZAN, TOKUSHIMA, HIZAN (HIYAMA), KOKKA, YASUKUNI, TENSHIN, MANTAI, MITSUKI and RYOFU MARUs and four unidentified merchant ships.
12 July 1944:
At 2110, arrives at Takao.
14 July 1944:
At 1900, W-34 departs Takao for Manila with kaibokan KUSAGAKI, CD-1, CD-22 and minelayers MAESHIMA and ENTO escorting convoy TAMA-21C consisting of MANTAI, MITSUKI, JINSAN, SEATTLE, YASUKUNI, TENSHIN, YAMATAMA, SAINEI, HIZAN (HIYAMA), KOKKA, SHOZAN, TOKUSHIMA and SHOKEI MARUs and tankers SHONAN, MITSU, AYAGIRI and AYAZONO MARUs and three unidentified merchant ships.
16 July 1944:
At 0946, LtCdr Harold E. Ruble's (USNA ’33) USS PIRANHA (SS-389) torpedoes and sinks SEATTLE MARU at 19-17N, 120-15E. The ship was carrying 4,285 IJNAF personnel. 45 crewmen, 25 gunners and 296 passengers and troops are KIA. HIYAMA and SHOZAN MARUs rescue all but 286 of the airmen. Over the next six hours, Captain William V. O'Regan’s (USNA ’23) wolf pack consisting of LtCdr Duncan C. MacMillian's (USNA ’26) USS THRESHER (SS-200), LtCdr (later Rear Admiral) Norvell G. Ward's (USNA ’35) USS GUARDFISH (SS-217) and Ruble's USS PIRANHA closes in and decimates the convoy.
At 2300, MacMillian's USS THRESHER torpedoes and sinks SAINEI MARU at 18-53N, 119-32E. 21 troops and passengers on board, and three crewmen are KIA. At 2350, Ward's USS GUARDFISH torpedoes and sinks JINZAN MARU. 38 troops, one passenger, seven gunners, two watchmen and three crewmen are killed – a total of 51 dead. Two minutes later, Ward torpedoes and sinks MANTAI MARU. 72 military passengers and 43 crewmen are KIA.
17 July 1944:
The attacks continue. At 0034, Ward's USS GUARDFISH torpedoes and sinks HIYAMA MARU. The ship was loaded with 2 companies of an Army group including the 12th Independent Tank Company with Type 95 light tanks and totaling 101 troops, of whom four along with four of the crew were KIA. W-34 and CD-1 rescue survivors. At 0345, MacMillian's USS THRESHER torpedoes and sinks SHOZAN MARU at 18-50N, 119-43E. 24 Gunners, 125 troops, 500 SEATTLE MARU survivors and 64 crewmen are killed. W-34 and CD-1 rescue the survivors.
19 July 1944:
At 1920, convoy TAMA-21C arrives at Manila.
23 July 1944:
At 0700, W-34 departs Manila with subchaser CH-21 escorting convoy MASA-09 consisting of RAKUYO and CHINZEI MARUs and tanker NICHINAN MARU.
28 July 1944:
At 1800, arrives at St Jacques (near Saigon), Indochina.
1 August 1944:
At 1100, W-34 departs Cape St. Jacques for Singapore escorting EIFUKU, NICHINAN and RAKUYO MARUs.
4 August 1944:
At 0150, anchors in the Kuantan Sea, E of Malaya. At 1010, departs.
5 August 1944:
At 1430, arrives at Singapore.
17 August 1944:
At 1300, departs Singapore in a convoy escorted by W-34, subchaser CH-8 and one other unidentified escort.
20 August 1944:
At 1340, arrives at Penang.
23 August 1944:
At 0730, departs Penang.
24 August 1944:
At 1000, arrives at Belawan. At 1440, departs Belawan.
28 August 1944:
At 0940, arrives at Sabang.
29 August 1944:
At 1200, departs Sabang escorting RISUI MARU (ex British LIPIS).
1 September 1944:
At 1640 arrives at Singapore.
14 September 1944:
At 1600 departs Singapore in convoy consisting of EIFUKU MARU and Landing Ship T-149 (unconfirmed).
17 September 1944:
Arrives off Kota Baru, Malaya.
19 September 1944:
At 1600, arrives at Saigon.
20 September 1944:
At 0940, departs Saigon.
22 September 1944:
At 2120, arrives at Singapore.
26 September 1944:
At 1100, departs Singapore.
30 September 1944:
At 1640, arrives at Penang.
1 October 1944:
At 1000, departs Penang.
5 October 1944:
At 1500, arrives at Singapore.
8 October 1944:
At 1000, departs Singapore with DAICHO MARU.
11 October 1944:
At 0900, arrives at Sabang and anchors in roadstead.
12 October 1944:
At 1000, enters Sabang Port. At 1510 departs Sabang.
15 October 1944:
At 1445, arrives at Singapore.
16 October 1944:
Hiyoshi. Headquarters, Combined Fleet's at Keio University. Chief of Staff Vice Admiral Kusaka Ryunosuke (41)(former CO of AKAGI) releases a dispatch that assigns W-34 to Vice Admiral Kurita Takeo's (38)(former CO of KONGO) First Striking Force's 1st Supply Force with tankers ITSUKUSHIMA, NICHIEI, YUHO, OMUROSAN, RYOEI and BANEI (MANEI) MARUs and kaibokan CHIBURI, minelayer YURISHIMA, kaibokan CD-19 and CD-27.
18 October 1944:
At 1300, departs Singapore in convoy consisting of tankers HAKKO and YUHO MARUs with destroyers MICHISIO, NOWAKI as additional escorts.
21 October 1944:
At 1200, arrives at Brunei/Labuan.
23 October 1944:
At 0610, departs Labuan.
25 October 1944:
At 1700, arrives at Singapore.
26 October 1944:
At 1800, departs Singapore.
29 October 1944:
At midnight arrives at Brunei.
30 October 1944:
Departs Brunei for Singapore in company of KISHINAMI, escorting HAGURO and the damaged MYOKO.
3 November 1944:
At 0120, arrives at Singapore.
4 November 1944:
At 1720, departs Singapore.
6 November 1944:
At 1020, arrives at Kuching.
7 November 1944:
At 0800, departs Kuching.
8 November 1944:
At 1650, arrives at Brunei. Departs at 1800.
11 November 1944:
At 1140, arrives at Singapore.
19 November 1944:
At 1000, W-34 departs Singapore with subchaser CH-35 escorting a convoy consisting of tankers NICHINAN, RITSUEI, SHONAN, SHOEI and AYAYUKI MARUs. At 1837, Lt C. R. Pelly's British submarine HMS STRATAGEM torpedoes and sinks NICHINAN MARU at 01-36N, 102-53E. Nine crewmen are KIA.
20 November 1944:
At 1822, aircraft attack the convoy, but inflict no damage.
22 November 1944:
At 1803, W-34 is detached from the convoy.
23 November 1944:
At 1805, arrives at Singapore.
26 November 1944:
At 1750, transfers to Eastern anchorage, Singapore.
27 November 1944:
At 0205, W-34 departs Singapore with kaibokan CD-27, subchasers CH-34 and CH-35 and auxiliary gunboat HUASHAN (KAZAN) MARU escorting convoy SHISA-30 consisting of EININ, TOHO, FUJISAN, HIKACHI (NISSHO), ENRYAKU, TATSUMIYA, YAMAKUNI and DAISHU MARUs en route to St Jacques.
30 November 1944:
At 2115 arrives at Nha Be, Indochina.
1 December 1944:
Arrives at Saigon.
2 December 1944:
4 December 1944:
Arrives at Singapore.
8 December 1944:
12 December 1944:
Arrives at St Jacques.
13 December 1944:
Departs St Jacques and later that day arrives at Saigon.
14 December 1944:
20 December 1944:
Arrives at Singapore.
21 December 1944:
At 2003, W-34 receives the order to join the damaged heavy cruiser MYOKO, towed towards Singapore, and provide her with anti-submarine cover. The ship departs Singapore later that day.
23 December 1944:
At 0817 patrol boat PB-104 meets up with and begins escorting damaged cruiser MYOKO also now escorted by minelayer YURIJIMA and minesweeper W-34.
25 December 1944:
At 0145 arrives at Singapore.
8 January 1945:
11 January 1945:
Arrives at Sabang.
12 January 1945:
At 2000 departs Sabang with submarine chasers CH-34, CH-35 and CH-63 escorting EIFUKU MARU.
15 January 1945:
At 1930 arrives at Singapore.
20 January 1945:
W-34 departs Singapore with subchaser CH-34 escorting convoy SHISA-34 consisting of the tanker SERIA MARU.
23 January 1945:
Arrives at St Jacques and departs later that day.
24 January 1945:
Arrives at Saigon.
25 January 1945:
30 January 1945:
Arrives at Saigon.
31 January 1945:
1 February 1945:
W-34 arrives at and then departs St Jacques with subchaser CH-34 escorting convoy SASHI-41C consisting of tanker NANSHIN MARU No. 19 and six unidentified merchant ships.
2 February 1945:
At about 2300, LtCdr Francis A. Greenup’s (USNA ’36) USS HARDHEAD (SS-365) torpedoes and sinks NANSHIN MARU No. 19 at 04-00N 102-36E. 10 crewmen are KIA.
7 February 1945:
Convoy SASHI-41C arrives at Singapore.
10 February 1945:
Departs Singapore escorting a convouy consisting of tanker RITSUEI MARU and possibly others.
16 February 1945:
Arrives at St Jacques.
19 February 1945:
Departs St Jacques.
24 February 1945:
Arrives at Singapore.
8 March 1945:
At 1220 departs Surabaya on a transport mission and joins up with minesweepers W-11 and W-12 and torpedo boat KARI that had departed earlier that day.
13 March 1945:
At 1730 W-11, W-12, W-34 and KARI arrive back at Surabaya.
24 March 1945:
At 1200 W-34 departs Surabaya and joins W-11 and W-12 on an anti submarine sweep and then an escort mission.
28 March 1945:
W-34 and W-11 arrive at Makassar escorting convoy SUMA-4 consisting of unidentied ships.
Off Makassar. W-11 is attacked by 13th Air Force B-24 "Liberator" heavy bombers and sunk at 05-06S, 119-14E.
At 2113, USN codebreakers intercept and decrypt a message that reads: “1. Minesweeper No. 34 proceed as scheduled at top speed to Surabaya. 2. Rescue Guard Force No. 3 engage in rescue of survivors of minesweeper No. 11.”
30 March 1945:
At 1100 W-34 arrives back at Surabaya.
4 April 1945:
W-34 departs Surabaya with torpedo boat KARI and minesweeper W-12 escorting light cruiser ISUZU. Off Paternoster Island, the ISUZU group is sighted by a wolf pack led by Cdr (later Rear Admiral) Francis D. Boyle's (USNA ’34) USS CHARR (SS-328) with LtCdr Herman E. Miller's (USNA ’38) USS BESUGO (SS-32l) and LtCdr William B. Parham's (USNA ’36) USS GABILAN (SS-252), but 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 by ComSubSoWestPac's British submarine HMS SPARK.
Kupang Harbor. At dawn, ISUZU embarks an army detachment and departs for for Sumbawa Island. North of Sumbawa she 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 off her starboard bow by some of the sixty 300-kg bombs dropped. 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 section 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 one sinks W-12.
7 April 1945:
At 0220, W-34 departs Bima with ISUZU and KARI. USS CHARR makes radar contact at 14,000 yards and Boyle alerts USS GABILAN.
60 miles NW of Bima. At 0605, ISUZU is struck by a torpedo fired by Parham's USS GABILAN. The torpedo hits portside below the bridge and causes flooding forward. ISUZU's speed falls below 10 knots, she takes on a list and is down by the bow.
At 0827, while ISUZU's crew is performing emergency repairs, Boyle's USS CHARR fires four torpedoes at her from 1,200 yards. She is hit portside near the aft engine room by two torpedoes. Boyle fires two more torpedoes and gets another hit. At 0843, ISUZU's bow breaks off. At 0846, she capsizes to port and sinks at 07-38S, 118-09E. W-34 and KARI counter-attack USS CHARR, but Boyle goes deep and evades.
W-34 and KARI rescue 450 of ISUZU's crewmen.
8 April 1945:
At 1800 arrives back at Surabaya.
22 April 1945:
At 1300 departs Surabaya on an escort mission.
28 April 1945:
At 1215 arrives back at Surabaya.
14 May 1945:
On that day, FRUMEL decrypts the following message from Surabaya, timed 131842:
"1) At 0630 on 13th in 5-34S 111-16E YOOSEI MARU was torpedoed by enemy submarine and sunk. ENOSHIMA MARU is anchored at Rembang and No. 17 SHOONAN MARU is engaged in keeping this submarine down.
2) Minesweeper 34 sails tomorrow to attack, then escort ENOSHIMA to Cheribon."
(Comment: YOSEI MARU, ENOSHIMA MARU and SHONAN MARU No. 17 formed a convoy which left Soerabaja for Palembang on 11th. YOSEI MARU had a cargo of rice and empty oil drums).
19 May 1945:
On that day, FRUMEL provides the following information from SHONAN MARU No. 2:
"Minesweeper 34 leaves Soerabaja on 20th for Makassar where 250 Army troops and 5 tons of freight are to be embarked and brought back to Soerabaja."
21 May 1945:
E of the Java Sea. Off Kepulauan, Java. W-34 is hunting for an enemy submarine that attacked two Japanese freighters in the area the previous afternoon.
At about 0200, Cdr Cassius D. Rhymes’ submerged (USNA ’35) USS CHUB (SS-329) picks up a sonar echo and closes. Rhymes fires five torpedoes at the sonar return. One torpedo hits and sinks W-34 at 06-18S, 116-14E.
At 1645, USN codebreakers intercept and decrypt a message that reads: “-- At 1430 finished picking up the 78 survivors including the captain of W-34 (among them 20 --, 25 lightly injured and 2 --) -.”
Another message says W-34 was sailing from Surabaya to Makassar.
29 May 1945:
At 1505, codebreakers intercept and decrypt a message that reads: “Circumstances concerning the search for the codebooks following the sinking of W-34 as reported in ----- are as follows: 1. W-34 was struck below the #3 gun turret by one torpedo on the 21st at 0302, at (06 ?)-04 S., 116-04 E. The -- (side ?) of the -- was smashed and the ship sank in about five minutes. ----.” Another message estimates 06-17 S., 116-04 E.
10 June 1945:
Removed from the Navy List.
 Dutch sources claim the aircraft and the squadrons involved in the strike were: No. 18 Dutch Squadron - 10 B-25s, No. 2 RAAF Squadron - 10 B-25, and No. 82 RAAF Wing - 9 B-24s. Two of the B-24s that attacked about 20 minutes later were shot down by Japanese Army fighters (probably Nakajima KI-43 "Oscars" and/or Nakajima KI-44 "Tojos").
Thanks for assistance with IJN COs go to Matthew Jones of Tennessee, USA. Thanks for assistance also go to fellow researchers Sander Kingsepp of Estonia and Gilbert Casse of France. Thanks also go to the late John Whitman of Virginia, USA for info on CNO intercepts of Japanese messages. Special thanks go to Hans Mcilveen of the Netherlands for info on FRUMEL intercepts.
Photo credit goes to Gakken via J. Ed Low.
-Bob Hackett and Peter Cundall.