KUSENTEI!

© 2005-2009 Bob Hackett, Sander Kingsepp and Peter Cundall

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19 June 1933:
Tokyo. Laid down at the Uraga dockyard.

23 December 1933:
Launched and numbered CH-1.

28 December 1938:
Completed and registered in the IJN.

7 December 1941: Operation "M" - The Invasion of the Northern Philippines:
CH-1 is in Rear Admiral (later Vice Admiral) Kubo Kyuji’s (38) (former CO of KAGA) 1st Base Force of Vice Admiral Takahashi Ibo’s (35)(former CO of YAMASHIRO) Third Fleet. CH-1 is attached to Takahashi's Philippines Seizure Force in LtCdr Okawara’s SubChasDiv 1 with CH-2 and CH-3. At 1630, departs Mako, Pescadores.

10 December 1941:
Beginning at 0550, participates in the landings at Aparri, Philippines.

9 January 1942: Operation "H" - The Invasion of Celebes, Netherlands East Indies:
Light cruiser NAGARA, patrol boats PB-1, PB-2, PB-34, MineSweepDiv 21's W-7, W-8, W-9, W-11 and W-12 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 NAGARA, MineSweepDiv 21, patrol boats and SubChasDiv 1’s CH-1, CH-2 and CH-3 provides escort for the Menado invasion force of eight transports carrying 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.

31 January 1942: The Invasion of Ambon Island, Netherlands East Indies:
The convoy's escort is provided by Rear Admiral (later Vice Admiral) Tanaka Raizo in light cruiser JINTSU with DesDiv 8's DesDiv 15 and DesDiv 16, MineSweepDiv 21, SubChasDiv 1 CH-1, CH-2 and CH-3 and patrol boats P-34 and P-39. The convoy's air cover is provided by CarDiv 11's MIZUHO and the CHITOSE. CruDiv 5's NACHI and HAGURO, DesDiv 6's IKAZUCHI and DesDiv 7's USHIO and SAZANAMI provide the covering force.

5-10 February 1942: The Invasion of Makassar, Celebes:
Rear Admiral Kubo’s 1st Base Force with NAGARA, MineSweepDiv 21, SubchasDiv 2 and SubChasDiv 1’s CH-1, CH-2 and CH-3 provides escort for the Makassar invasion force of six transports carrying Mori's Sasebo Combined SNLF.

10 March 1942:
Assigned to Vice Admiral Takahashi's Southwest Area Fleet's newly formed Second Southern Expeditionary Fleet in Special Base Force 21's SubChasDiv 1 organized at Surabaya.

1 May 1942:
SubChasDiv 1 is disbanded. CH-1 is reassigned to SubChasDiv 2 in the Yokosuka Naval District with CH-2 and CH-3.

May 1942-October 1944:
CH-1 escorts convoys. [1]

25 February 1944:
LtCdr Willard R. Laughon's USS RASHER (SS-269) intercepts a convoy consisting of RYUSEI and TANGO MARUs that is proceeding from Surabaya to Ambon escorted by minesweepers W-8 and W-11 and auxiliary subchaser TAKUNAN MARU No. 3. RYUSEI MARU is carrying about 6600 men of various IJA units. At 2045, Laughon torpedoes and sinks TANGO MARU about 25 miles N of Bali Island at 07-41N, 115-10E. At 2225, Laughon sets up and fires four torpedoes at RYUSEI MARU. He gets three hits and she goes down at 07-55S, 115-15E taking 4,998 troops and crewmen with her.

At 0824, USN codebreakers intercept and decrypt a message that reads: "Subchaser No. 1 will proceed immediately to the position of the sinking of the RYUSEI MARU to rescue personnel.”

19 October 1944:
CH-1, CH-3, CH-19, auxiliary minesweepers CHOUN MARU No. 6 and CHOUN MARU No. 7 depart Miri escorting convoy MISHI-11 consisting of 16 unidentified merchant ships.

23 October 1944:
Arrives at Singapore.

1 November 1944:
CH-1, CH-19, CH-26 and CH-36 depart Singapore for Manila escorting convoy SIMA-04 consisting of HACHIJIN, AYAGIRI, ATSUTA and TOYO (YUTAKA) MARUs.

2 November 1944:
225 miles E of Singapore. At 1717, Lt (later Vice Admiral Sir) Hugh "Rufus" MacKenzie's British submarine HMS TANTALUS attacks the convoy. In heavy weather, MacKenzie torpedoes and sinks cargo ship HACHIJIN MARU and damages CH-1 at 00-45N, 107-441E.

14 November 1944:
Rear Admiral (later Vice Admiral) Frederick C. Sherman, in temporary command of Task Force 38, launches air strikes against shipping in the Philippines. Off Sablayan Island, Mindoro, convoy SIMA-04 is attacked by F6F “Hellcat” fighter-bombers from USS YORKTOWN (CV-10). The Hellcats sink merchant oiler AYAGIRI MARU at 12-40N, 120-41E and damage IJA cargo ship TOYO MARU and CH-1, CH-19, CH-26 and CH-36.

29 November 1944:
CH-1 and minesweeper W-20 depart Manila escorting convoy MASHI-12A consisting of two unidentified merchant ships.

E 4 December 1944:
Arrives at Singapore. Thereafter, CH-1 undergoes repairs.

26 May 1945:
At 1258, USN codebreakers intercept and decrypt a message that reads: “-- CH-1 will depart immediately for vicinity of Mandalike Island to capture or sink the enemy submarine which attacked special [auxiliary] minesweeper Wa-105 and KAMISHIMA MARU there around 1400 May 25th --.”

28 May 1945:
Off Japara, Dutch East Indies. At 2135, CH-1 is damaged in a gun action by LtCdr Merrill K. Clementson's USS BLUEBACK (SS-326) and LtCdr Lucien B. McDonald's LAMPREY (SS-372) at 06-28S, 110-37E.

At 1258, USN codebreakers intercept and decrypt a message from CH-1 that reads: “At 2135 on the 28th submarine certain in position 06-28S, 110-37E.”

29 May 1945:
At 0755, codebreakers decrypt a message from CH-1 that reads: “In the engagement with two enemy submarines off Japara on May 28th lasting about 30 minutes after 2115, the following facts were considered of tactical value --(description of allied methods of attack)--.”

16 July 1945:
W of Surabaya, Java. At 0430, CH-1 is escorting gunboat NANKAI (ex-Dutch minelayer REGULUS) when they are attacked by LtCdr William H. Hazzard's USS BLENNY (SS-324). Hazzard fires a total of 12 torpedoes in a night surface radar attack and claims four hits that sink NANKAI at 05-26S, 110-33E.

At about 0700, Hazzard finds and shells CH-1 with his 5-inch deck gun. BLENNY gets two hits that set CH-1 on fire at 05-16S, 110-17E.

19 July 1945:
At 1545, USN codebreakers intercept and decrypt a message that reads: “NANKAI was enroute Singapore from Surabaya via Batavia engaged in transportation operation under escort of CH-1 when she was attacked by an enemy submarine which fired two torpedoes. She probably sank --- 0430 on July 16th in position 05-16S, 110-17E. The vicinity was swept by CH-1 and a float reconnaissance plane. On the 17th the float reconnaissance plane ------ floating in position 05-07S, 110-19E. Further search was carried out by CH-5 and SHONAN MARU No. 17 but neither survivors nor flotsam were seen. Secret documents apparently sank with the hull.”

11 July 1946:
Singapore. CH-1 is scuttled by the Royal Navy.

10 August 1946:
Removed from the Navy List.

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Author's Notes:
[1] Litle data were found detailing CH-1's movements during the timeframe of May 1942-October 1944. Readers with access to such data are requested to post the information on the Discussion and Questions board or at j-aircraft.org's IJN Ship Message Board

Thanks for assistance go to Cdr John D. Alden, USN-Ret. Thanks also go to John Whitman of the USA for info on CNO intercepts of Japanese messages.

-Bob Hackett, Sander Kingsepp and Peter Cundall.

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