Japanese Auxiliary Gunboats

KOKAI HOKAN!

(CHOHAKUSAN MARU, prewar)

IJN CHOHAKUSAN MARU:
Tabular Record of Movement

© 2020 Gilbert Casse, Berend van der Wal and Peter Cundall

21 December 1927:
Uraga. Laid down by Uraga Senkyo K.K. shipyard for Chosen Yusen K.K. as a 2,131-tons cargo ship.
27 March 1928:
Launched and named CHOHAKUSAN MARU. [1]
25 June 1928:
Completed and registered at Jinsen, Chosen (now Inchon, South Korea) with a Gross Registered Tonnage (GRT) of 2,131-tons and a Net Registered Tonnage (NRT) of 1,240 tons. Her call sign is PHGD. [2]
1931:
Her NRT is changed to 1,243-tons. [2]
1 December 1932:
Her call sign is changed to JQSB.
17 July 1937:
Enters drydock.
4 November 1937:
Requisitioned by the IJN.
5 November 1937:
Registered as an auxiliary gunboat attached to the Yokosuka Naval district under instruction No. 788. Navy Cdr Taniguchi Gousuke (41) is appointed CO.
7 November 1937:
Attached to the Second Gunboat division.
15 November 1937:
Tama. Conversion to military duty begins at Tama K.K. shipyard.
27 November 1937:
Attached to Vice Admiral (later Admiral) Toyoda Soemu’s (41) Fourth Fleet, Second Gunboat Division.
29 November 1937:
Conversion is completed. Departs Tama and arrives at Kure later this day.
6 December 1937:
At Ryojun (Port-Arthur, Lushun), Manchuria (now Lushunkou, northern China). Lies alongside auxiliary gunboat SHINKAI MARU.
9 December 1937:
Auxiliary gunboat DELHI MARU lies alongside to starboard.
11 December 1937:
Departs Ryojun.
15 December 1937:
Arrives at Jinghai Bay, Shandong Province, China. Later returns to Ryojun.
18 December 1937:
Auxiliary gunboat CHOHEI MARU lies alongside to starboard. Later departs Ryojun.
20 December 1937:
Arrives at Ryojun. Lies alongside auxiliary gunboat CHOHEI MARU.
24 December 1937:
Departs Ryojun.
26 December 1937:
Sends a cutter to auxiliary gunboat DELHI MARU, delivers mail, various items and transfers two passengers.
4 January 1938:
Arrives at Ryojun. Lies alongside to auxiliary gunboat CHOHEI MARU.
5 January 1938:
Departs Ryojun for the Li Changshan Islands, China.
8 January 1938:
Arrives at Seito (Tsingtao, now Qingdao), China.
11 January 1938:
Departs Tsingtao.
14 January 1938:
Arrives at Ryojun. At 1126, auxiliary gunboat DELHI MARU lies alongside to starboard.
17 January 1938:
Departs Ryojun for Chefoo (Zhifu, now Yantai), China.
20 January 1938:
Arrives at Seito and anchors.
E20 ~ 31 January 1938:
Departs Seito for Weihai Wei, China.
3 February 1938:
Departs Weihai Wei and calls at Chefoo. Departs there and arrives at Weihai Wei later that day.
7 February 1938:
Departs Weihai Wei. 1000 ~ 1009: executes machine gun trial. Arrives at Dairen (now Dalian), China at the fourth port pier No. 47.
8 February 1938:
1049 ~ 1410: a water boat lies alongside to port bow. At 1700, loads coal.
9 February 1938:
1300 ~ 1650: a water boat lies alongside to port.
10 February 1938:
Departs Dairen and arrives at Chefoo later that day.
11 February 1938:
Departs Chefoo and arrives at Weihai Wei later this day.
14 February 1938:
Anchors at 357° and about one nautical mile off Weihai Wei port lighthouse.
16 February 1938:
Anchors at 15° and about one nautical mile off Weihai Wei port lighthouse. Later this day anchors at 118° and about 1.5 nautical mile off Weihai Wei port lighthouse.
18 February 1938:
Anchors at 2° and about one nautical mile off Weihai Wei port lighthouse.
19 February 1938:
Transfers goods to a fireboat near the pier.
22 February 1938:
Departs Weihai Wei and arrives at Ryojun, at E port W shore.
24 February 1938:
At 0930, loads food.
26 February 1938:
Departs Ryojun.
27 February 1938:
Arrives at Chefoo. Departs there and arrives at Huang County (now Longkou) later that day.
28 February 1938:
Anchors at 155° and about 2.5 nautical miles off Qi Mu Yue lighthouse.
1 March 1938:
Explores the harbor in one of her own ship boats.
3 March 1938:
Anchors. 2034 ~ 2200: illuminates the shore with searchlights.
4 March 1938:
0335 ~ 0421: switches on searchlights.
8 March 1938:
Anchors.
13 March 1938:
Departs Huang County.
14 March 1938:
Arrives at Ryojun at the E port W shore. 1040 ~ 1645: loads boiler water and coal.
16 March 1938:
Departs Ryojun.
17 March 1938:
Calls at Chefoo. Departs there and arrives at Huang County later this day.
18 March 1938:
2000 ~ 2037: performs searchlight training.
19 March 1938:
Anchors.
22 March 1938:
2020 ~ 2105: switches on searchlights.
23 March 1938:
2020 ~ 2140: switches on searchlights. At 2022, dispatches a launch to Chinese ship BEIJING. At 2030, BEIJING is captured and will sail to Chefoo.
24 March 1938:
At 0820, dispatches BEIJING crew group No. 1 and at 0945, dispatches BEIJING crew group No. 2. Departs Huang County later that day.
25 March 1938:
Arrives at Chefoo. At 0419, one BEIJING crew member returns. Departs there and arrives at Dairen later that day.
26 March 1938:
0945 ~ 1350: a water boat lies alongside to starboard amidships.
1045 ~ 1510: a coal barge lies alongside to starboard and transfers coal.
27 March 1938:
0830 ~ 0930: loads food.
28 March 1938:
Departs Dairen and arrives at Chefoo later that day.
29 March 1938:
Departs Chefoo for Huang County but reverses course and arrives back at Chefoo later this day.
30 March 1938:
1930 ~ 2010: loads ammunition.
4 April 1938:
Changes anchorage to Chefoo outer harbor.
E4 ~ 7 April 1938:
Departs Chefoo.
7 April 1938:
Arrives at Ryojun.
10 April 1938:
Departs Ryojun for Huang County.
21 April 1938:
Departs Huang County.
22 April 1938:
Arrives at Dairen.
25 August 1938:
Departs Dairen.
26 August 1938:
Arrives at Huang County.
1 May 1938:
Departs Huang County.
6 May 1938:
Arrives at Ryojun. At 1620, lies alongside to auxiliary gunboat CHOHEI MARU starboard.
8 May 1938:
Departs Ryojun and calls at Nan Huang Cheng Island, China. Departs there later that day.
9 May 1938:
Arrives at Ryojun. Lies alongside auxiliary gunboat SHINKAI MARU.
13 May 1938:
Departs Ryojun.
14 May 1938:
Arrives at Huang County and anchors in inner harbor.
24 May 1938:
Depart Huang County.
25 May 1938:
Arrives at Ryojun.
28 May 1938:
Departs Ryojun and arrives at Chefoo later that day.
31 May 1938:
Anchors outside harbor.
1 June 1938:
Anchors outside harbor and later this day anchors inside harbor.
2 June 1938:
Departs Chefoo.
11 June 1938:
Arrives at Ryojun.
14 June 1938:
Departs Ryojun and arrives at Chefoo later that day.
18 June 1938:
Departs Chefoo and arrives at Huang County later that same day.
20 June 1938:
Departs Huang County with auxiliary gunboat SHINKAI MARU for a combined night exercise. Arrives at Ryojun later this day.
E20 ~ 21 June 1938:
Departs Ryojun and arrives at Huang County later that day.
22 June 1938:
Departs Huang County.
25 June 1938:
Arrives at Ryojun.
28 June 1938:
Departs Ryojun.
1 July 1938:
Joins auxiliary gunboat SHINKAI MARU for a combined training run.
6 July 1938:
1737 ~ 1930: joins auxiliary gunboat SHINKAI MARU for a ranging exercise. Arrives off Dahei Shan Island coast, China. Departs Dahei Shan Island waters later this day.
7 July 1938:
Arrives at Chefoo.
11 July 1938:
Departs Chefoo.
12 July 1938:
Arrives at Ryojun.
19 July 1938:
Departs Ryojun.
24 July 1938:
Arrives at Chefoo.
28 July 1938:
Departs Chefoo.
29 July 1938:
Arrives at Ryojun.
31 July 1938:
Departs Ryojun for Chefoo.
14 August 1938:
Departs Chefoo.
15 August 1938:
Arrives at Dairen.
19 August 1938:
Departs Dairen and calls at Huang Cheng Island, China. Departs there later this day.
31 August 1938:
Arrives at Ryojun.
3 September 1938:
Departs Ryojun and calls at Huang County. Departs there later this day.
5 September 1938:
Arrives at Chefoo.
8 September 1938:
Departs Chefoo.
11 September 1938:
Arrives at Ryojun.
15 September 1938:
Released from the Second Gunboat division and attached to the First Gunboat division under Auxiliary Gunboat division instruction No. 785.
16 September 1938:
Departs Ryojun for southern Chinese waters.
22 September 1938:
Arrives at Kirun, Formosa (now Keelung, Taiwan).
23 September 1938:
Departs Kirun.
9 October 1938:
Arrives at Zhangshan anchorage, China.
14 October 1938:
Departs Zhangshan anchorage.
7 November 1938:
Arrives at Kirun. Departs there later.
10 November 1938:
Ship CO is missing.
12 November 1938:
Arrives at Kure.
13 November 1938:
Detached from the First Gunboat division under Auxiliary Gunboat division instruction No. 934.
28 November 1938:
Removed from the Navy’s list under instruction No. 985 and released to her owners.
1 November 1941:
Requisitioned by the IJN again.
10 November 1941:
Registered as an auxiliary gunboat attached to the Sasebo Naval district under instruction No. 1389. Rated as an auxiliary gunboat engaged in minelaying. Navy (Resv) LtCdr Shimizu Jinji is appointed CO that same day.
17 November 1941:
Conversion to military duty begins at Tama Shipyard.
20 November 1941:
Attached to the Mako Guard District. Tactically attached to Kirun Defense Force under Mako Guard District instruction.
24 December 1941:
Conversion is completed.
27 December 1941:
South China Sea. 30 nms SW of Hong Kong. LtCdr David A. Hurt’s (USNA ’25) USS PERCH (SS-176) torpedoes and blows the bow off Fleet supply ship NOJIMA at 22-14N, 115-13E. She seeks shelter in Hong Hai Bai, China and subsequently runs aground.
Mako Defense Prefecture order No. 32:
Auxiliary gunboat CHOHAKUSAN MARU and auxiliary subchaser AKITSU MARU will depart Mako, Pescadores for Hong Hai Bay as soon as possible and assist damaged Fleet supply ship NOJIMA sheltering in the area after being attacked by an enemy submarine.
CHOHAKUSAN MARU CO commands AKITSU MARU from Mako until completing mission.
On board of CHOHAKUSAN MARU are 40 factory workers of the Mako Operations Manager and rescue materials.
Departs Mako with auxiliary subchaser AKITSU MARU.
28 December 1941:
Mako Defense Prefecture order No. 32 is cancelled for auxiliary subchaser AKITSU MARU and she is ordered to return to Mako.
29 December 1941:
Arrives at Hong Hai Bay and begins assisting supply ship NOJIMA.
3 January 1942:
Departs Hong Hai Bay.
4 January 1942:
Arrives at Mako.
14 January 1942:
After anti-submarine sweeping at Hachiman Waterway, China enters harbor.
15 January 1942:
Tactically assigned to Kirun Defense Force under Mako Security Desk instruction No. 7.
31 January 1942:
Departs Mako for Kirun.
2 February 1942:
Rescues unknown ship in distress.
15 February 1942:
As soon as auxiliary gunboat CHOHAKUSAN MARU is ready, to depart immediately and attack the enemy submarine that appears at 26-30N, 123-34E at 0200 on 15 Feb ‘42 under Mako Security Desk instruction No. 16.
9 March 1942:
Mako Security Desk instruction No. 24:
1 - HAWAII, KOFUKU and MEIU MARUs transporting the 4th division depart 9 Mar ‘42 at 1500 from Wuhu (Woosung), China to Lingayen Bay, Philippines. Approximate.
2 - Speed is 10 knots. Route: 5 nautical miles of N Saddle Island (Hua-Niao Shan) lighthouse, 3 nautical miles of E Saddle Island (Dong Ma’an Dao). 5 nautical miles of E Beyushan Island (Bei yu Shandao), 5 nautical miles of Bi Toujiao, Formosa. After that berth along E Formosa coast and thereafter sail along NW Formosa coast.
3 - CHOHAKUSAN MARU will act as escort in the homebase area.
Departs Kirun to escort HAWAII, KOFUKU and MEIU MARUs.
13 March 1942:
Arrives at Kirun. Soon after meets up with 4th Division, Contingent No. 2, convoy No. 2 sailing to Lingayen Gulf from Woosung. This convoy consists of HAKUSAN, MURORAN and SHINGO MARUs also escorted (part way) by destroyer KURI. At an unknown date and time CHOHAKUSAN MARU is detached.
28 March 1942:
At 0800, departs Mako for Camranh Bay, French Indochina (now Vietnam) with minelayer SOKUTEN escorting a convoy consisting of FUKKAI, KOCHI, TAIKAI, RYUZAN, TETSUYO, TEIKAI (ex-German FULDA), MONTREAL, SAMARANG and PENANG MARUs and YOSHIDA MARU No. 1.
30 March 1942:
Mako Security Desk instruction no.30:
1 - An army convoy heading for Ujina and consisting of OYO, TACHIBANA, BUJUN, SEIAN and NIYO (ex-Norwegian HAFTHOR) MARUs departs from Amami Oshima area at noon of 30 Mar ‘42.
2 - Auxiliary gunboat CHOHAKUSAN MARU is assigned as escort for this convoy and will hand over escort to the Sasebo Escort Unit near Amami Oshima.
Departs Kirun to escort OYO, TACHIBANA, BUSUN, SEIAN AND NIYO (ex- Norwegian HAFTHOR) MARUS in Amami Oshima area and arrives back at Kirun later this day.
17 April 1942:
Assigned to be on alert for Royal family passengers at Kirun from 10 till to 11 May ‘42 under Mako Security Desk instruction No. 486.
18 April 1942:
Assigned to prepare to leave harbor for the second time to assist auxiliary gunboat CHIYO MARU with towing a mud barge under Security wireless instruction No. 492.
23 April 1942:
Performs firefighting training in Penghu Channel (between Formosa and Pescadores).
26 May 1942:
Mako Guard District instruction No. 46:
1 - Temporarily repaired Army transport LISBON MARU is under command of the Army towing CO, IJA transport YOSHIDA MARU No. 1. [3]
11th Engineering Department boarded on ocean tug and salvage ship AKITSU MARU will assist the towing work.
2 - Assigned with auxiliary subchasers OYO and ROYO MARUs to escort YOSHIDA MARU No. 1 towing LISBON MARU, which had suffered a major engine breakdown. During this action, auxiliary gunboat CHOHAKUSAN MARU CO commands auxiliary subchasers OYO and ROYO MARUs.
3-5 - Omitted.
6 - After arriving in Hong Kong, auxiliary gunboat CHOHAKUSAN MARU CO will complete mission as appropriate and then will accommodate personnel and load ammunition.
28 May 1942:
Departs Kirun and arrives at Mako later that day.
30 May 1942:
Departs Mako with auxiliary ocean tug and salvage ship AKITSU MARU and subchasers OYO and ROYO MARUs escorting damaged IJA transport LISBON MARU towed by YOSHIDA MARU No. 1 and arrives at Hong Kong later this day.
4 June 1942:
Mako Guard District wireless No. 1:
1 - Omitted.
2 - Auxiliary gunboat CHOHAKUSAN MARU will be the Hong Kong Departing Army transport ship as soon as work under Mako Security instruction No. 46 part 6 is completed.
[To] guard YOSHIDA MARU No. 1 and return to Kirun via Mako.
3 - Mako Defense CO and auxiliary gunboat CHOHAKUSAN MARU CO should schedule an action plan and report it.
E4 ~ 9 June 1942:
Accommodates personnel and loads munitions. Departs Hong Kong escorting YOSHIDA MARU No. 1.
9 June 1942:
Arrives at Mako.
30 June 1942:
Mako Guard District order No. 39:
1 - First Escort Unit is scheduled to escort convoy No. 230 N at 1000 on 9 Jul ‘42.
2 - Auxiliary gunboat CHOHAKUSAN MARU will cooperate with First Escort Unit and escort convoy No. 230 near to Shioyama Islands. After completion, CHOHAKUSAN MARU returns to mission site.
3 - CHOHAKUSAN MARU should sail to Mako in 4 Jul ’42 morning.
2 July 1942:
Departs Kirun for Mako.
6 July 1942:
Departs Mako with auxiliary gunboat PEKING MARU escorting convoy No. 230 consisting of auxiliary oiler SHOYO (7,499 GRT), HAKUBASAN, TAIBUN, TEIHOKU, WAKATSU, SHOGEN, NAGANO, MURORAN, RYUUN, HAMBURG, TAIKA, BRAZIL, NORFOLK and GINYO MARUs, MIKAGE MARU No. 3 and one unidentified merchant ship .
8 July 1943:
Arrives at Kirun.
14 July 1942:
Tactically assigned to Kirun Defense Force under Mako Guard District order No. 43.
22 August 1942:
Departs Kirun on an anti-submarine sweep.
28 August 1942:
Arrives at Kirun.
4 September 1942:
Departs Kirun and returns there later that day.
7 ~ 9 September 1942:
Performs first combined exercise.
14 September 1942:
Departs Kirun.
15 September 1942:
Arrives at Kirun.
27 September 1942:
Departs Kirun.
28 September 1942:
Arrives at Mako.
28 September ~ 1 October 1942:
Performs second combined exercise.
2 October 1942:
Departs Mako and returns there later that day.
7 ~ 8 October 1942:
Dispatch training.
12 ~ 14 October 1942:
Performs third combined exercise.
14 October 1942:
Mako Guard District instruction No. 71:
1 - At 1610, at 25-20N, 121-1E, TEISON MARU (ex-French VILLE DE VERDUN) was damaged by a torpedo attack.
2 - Kirun Defense Force units should use their full strength to find and destroy the enemy submarine. [4]
15 ~ 18 October 1942:
Together with auxiliary netlayer IWATO MARU , carries out anti-submarine sweeping and rescue of TEISON MARU.
17 October 1942:
Mako Guard District instruction No. 29:
1 – 2 - Omitted.
3 - Kirun Defense Force should continue executing Mako Guard District instruction No. 71.
18 October 1942:
Mako Guard District instruction No. 72:
1 - At 1220, at 25-15N, 121-55E TANGO MARU was attacked by enemy submarine with no damage sustained. 2 - Kirun Defense Force should abort Mako Guard District instruction No. 71 and find and destroy the enemy submarine that attacked TANGO MARU (6,893 GRT ).
19 ~ 23 October 1942:
Carries out anti-submarine sweeping in the Kirun area.
21 October 1942:
Mako Guard District instruction No. 74, partly corrected by Mako Guard District Secretary Instruction No. 211620:
1 - Around 0120, at 24-26N, 120-26E AFRICA MARU sank after been torpedoed by an enemy submarine.
2 – 3 - Omitted.
4 - CHOHAKUSAN MARU should work together with Kirun Defense Force to find and destroy the enemy submarine as soon as she is ready. [5]
Mako Guard District instruction No. 75:
CHOHAKUSAN MARU is not concerned by Mako Guard District instruction No. 74. CHOHAKUSAN MARU should return to Kirun.
25 October 1942:
Mako Guard District instruction No. 4:
1 - Army transport HIMALAYA MARU headed for Kirun is missing. Last known position was 20 nautical miles off Suao , Formosa at 0300 on 23 Oct ‘42.
2 - Kirun Defense Forces should search for HIMALAYA MARU.
25 ~ 27 October 1942:
Searches for HIMALAYA MARU. [HIMALAYA MARU, a straggler from Convoy No. 177, later arrived at Mako safely].
27 October 1942:
Mako Guard District instruction No. 5:
Searching mission under Mako Guard District instruction No. 4 is ended.
4 November 1942:
Departs Kirun.
25 November 1942:
Arrives at Kirun.
11 ~ 13 December 1942:
Executes first combined exercise.
17 December 1942:
Departs Kirun and returns there later that day.
28 December 1942:
Departs Kirun and returns to port later that same day.
28 ~ 30 December 1942:
Executes second combined exercise.
5 January 1943:
Departs Kirun and returns there later in the day.
11 ~ 13 January 1943:
Exercises alone.
15 January 1943:
Departs Kirun and returns to port later that day.
21 January 1943:
Departs Kirun and returns there later that day.
25 ~ 28 January 1943:
Exercises alone.
4 ~ 6 February 1943:
Executes fifth combined exercise.
24 ~ 26 February 1943:
Executes sixth combined exercise.
1 March 1943:
Mako Guard District instruction No. 7:
1 - At 0900, a Hsinchu, Formosa based aircraft discovers a submerged enemy submarine 330° and 25 nautical miles off Kannon lighthouse, Formosa. The aircraft lost contact at 0930. Enemy course was 170°.
2 - Kirun Defense Units CO should use all his units in anti-submarine sweep. CHOHAKUSAN MARU should only be used at night. Mako Defense Command CO is in command of this anti-submarine squadron.
Departs Kirun on an anti-submarine sweep later that day.
4 March 1943:
Mako Guard District instruction No. 9:
If you want to obtain enemy activity, stop the anti-submarine sweeps assigned in Mako Security Office instruction No. 7 and No. 9 on 4 Mar ‘42 after 1200. Kirun area Defense Forces should make a round voyage to Kirun as determined by CO.
5 March 1943:
Arrives at Kirun.
7 March 1943:
At 2250, TANGO MARU reports a torpedo attack in 26-50N, 122-37E.
8 March 1943:
At 0825, departs Kirun followed at 0900 by minelayer SOKUTEN and auxiliary patrol boats NITTO MARU No. 21, NITTO MARU No. 22 and YOKAI MARU to intercept and destroy the submarine and protect inbound Army transport OYO MARU.
9 March 1943:
At 0755, an enemy submarine is detected and depth charged in position 25-51N 123-34E. Attacks continue throughout much of the day until 1516 and submarine is claimed as sunk.
15 March 1943:
Mako Guard District instruction No. 18:
1 - At 1300, 25-33N, 121-53E FUJI MARU was torpedoed by an enemy submarine.
2 - Kirun Defense Units have to destroy this enemy submarine with every available resource.
18 March 1943:
Mako Guard District instruction No. 22:
Stop Mako Guard District instruction No. 18.
19 March 1943:
Off Kirun. Alerted by a codebreaker’s “Ultra” signal, LtCdr (later Vice Admiral) Vernon L. Lowrance’s (USNA ’30) USS KINGFISH (SS-234) intercepts troop transport (A/C-APK) TAKACHIHO MARU with 917 passengers and 2,614-tons of general cargo enroute to the Philippines escorted by minelayer SOKUTEN. At about 0900, USS KINGFISH torpedoes and sinks TAKACHIHO MARU at 25-50N, 122-30E. 98 crewmen out of 176 and 741 passengers are KIA.
20 March 1943:
Mako Guard District instruction No. 24:
1 - At 1500, on 19 Mar ‘43 at 25-27N, 122-17E something that looks like a submerged enemy submarine was discovered.
2 - Kirun Defense Units should take part in an anti-submarine sweep.
21 March 1943:
Mako Guard District instruction No. 25:
Kirun Defense Units main task is to rescue TAKACHIHO MARU survivors while the anti-submarine sweeping assigned in Guard District instruction No. 24 will be taken over by Mako Guard District Units.
At 0100, at 25-58N, 122-18E a surfaced submarine is discovered. At 0144, at 25-55N, 122-17E drops depth charges. At 0314, again drops depth charges.
23 March 1943:
At about 0430, SOKUTEN, attached to Mako Guard District, spots a surfaced submarine. SOKUTEN subjects USS KINGFISH (SS-234) to a severe depth charge attack. A squealing propeller shaft on the submarine aids the minelayer in locating USS KINGFISH (SS-234). Mako Guard District HQ next directs auxiliary gunboat CHOHAKUSAN MARU, auxiliary subchasers NITTO MARU No. 21 and No. 22 and YOBAI MARU to the same position.
At 1200, CHOHAKUSAN MARU drops 6 depth charges. At 1326, again drops depth charges.
USS KINGFISH (SS-234) briefly surfaces, revealing six meters of her bow before disappearing again.
After 1326, a substantial amount of diesel oil is sighted. The six ASW vessels drop 41 depth charges, the majority by SOKUTEN and CHOHAKUSAN MARU. The last string of depth charges smashes in the main induction piping allowing a huge bubble to escape to the surface. This apparently causes SOKUTEN’s captain to think the submarine had been sunk.
24 March 1943:
The chase continues until the morning over a 24 nm long distance. After a 16-hour ordeal, USS KINGFISH (SS-234) cautiously surfaces, clears the area and heads for Pearl Harbor.
25 March 1943:
Mako Guard District instruction No. 28:
Stop rescuing mission as mentioned in Mako Guard District instruction No. 24.
31 March 1943:
Departs Kirun.
1 April 1943:
Arrives at Kirun. Attached to Takao Guard District Unit. Tactically assigned to the Kirun Defense Force under Takao Guard District instruction No. 6.
12 April 1943: BR> Departs Kirun.
13 April 1943:
Arrives at Kirun.
22 April 1943:
Departs Kirun.
23 April 1943:
Arrives at Kirun.
3 ~ 8 May 1943:
Executes eleventh combined exercise.
9 May 1943:
Departs Takao, Formosa (now Kaoshiung, Taiwan) on a rescue mission.
10 May 1943:
Arrives at Kirun.
31 May 1943:
Departs Kirun and returns to port later this day.
1 June 1943:
Scheduled for tactical assignment to the Maritime Defense Force on 8 Jun ‘43 under Takao Guard Office instruction No. 15. LtCdr Shimizu is confirmed as CO.
7 June 1943:
Departs Kirun.
8 June 1943:
Arrives at Takao.
12 June 1943:
Departs Takao on rescue mission.
18 June 1943:
Arrives at Takao.
19 June 1943:
Tactically commanded by Hainan Guard District CO in chief under instruction No. 252.
20 June 1943:
Hainan Guard District instruction No. 16
1 - Scheduled to sail to Yulin Harbor, Hainan Island, China via Takao main harbor and commanded by Hainan Guard District CO in chief on 22 Jun 43’.
2 - Fast minelaying track will be repaired at Mako and equipped with 200 Type 93 mines.
Lay a deep minefield outside Yulin Harbor under Hainan Guard District instruction No. 20.
22 June 1943:
Departs Takao and arrives at Mako later that day.
22 ~27 June 1943:
Undergoes ship bottom inspection.
25 June 1943:
Navy (Resv) Lt Ishiwari Tadashi is appointed CO.
27 June 1943:
Departs Mako.
1 July 1943:
Arrives at Samah (now Sanya), Hainan Island. Navy (Resv) Lt Ishiwari Tadashi is confirmed as CO.
25 July 1943:
Departs Samah.
26 July 1943:
Hainan Guard District CO in Chief command is ended.
27 July 1943:
Arrives at Mako.
30 July 1943:
Departs Mako and arrives at Takao later this day.
9 August 1943:
Departs Takao for seventeenth combined exercise.
11 August 1943:
Arrives at Takao.
25 ~ 27 August 1943:
Executes eighteenth combined exercise.
4 September 1943:
Scheduled for anti-submarine sweeping under Takao Guard District instruction No. 254.
90 Km. SW Takao. At 0115, LtCdr Richard W Petersen’s (USNA ‘31) USS SUNFISH (SS-281) fires four torpedoes and gets one hit in IJA transport KOZAN MARU's No. 3 hold. Nine crewmen and thirteen passengers are KIA.
Departs Takao. At 1157, arrives at the sweeping area. At 1340, starts towing KOZAN MARU off Zuo Ying. At 2055, towing ends and KOZAN MARU subsequently is run aground and abandoned.
7 September 1943:
Takao Guard District instruction No. 256:
Stop anti-submarine sweeping if the enemy submarine isn’t destroyed by 1200. Arrives at Takao later that day.
22 September 1943:
Scheduled for tactically assignment to the Maritime Defense Force on 1 Oct ‘43 under Takao Guard District instruction No. 21.
27 September 1943:
Departs Takao on twentieth combined exercise.
29 September 1943:
Arrives at Takao.
1 October 1943:
Departs Takao on escort mission.
5 October 1943:
At 0900, departs Takao escorting convoy No. 209 consisting of auxiliary transport HOKKAI and RYUKO MARUs, IJA shared tanker (A/C-AO) TONAN MARU and seven unidentified ships.
7 ~ 9 October 1943:
Executes twenty-first combined exercise.
11 October 1943:
Arrives at Sasebo.
12 October 1943:
Arrives at Moji.
13 October 1943:
Departs Sasebo escorting a convoy.
20 October 1943:
Arrives at Sasebo.
22 October 1943:
Departs Sasebo, meets up and begins escorting the second part of convoy No. 108 consisting of SHINWA, KOSHU (2,612 GRT), MADRAS, TOTTORI, HASSHU, HEIMEI, OTORISAN, SEATTLE MARUs, auxiliary tankers KYOEI MARU No. 7 and UNKAI MARU No. 12 and two unidentified merchant ships.
23 October 1943:
The convoy arrives at Tomie.
25 October 1943:
Departs Tomie apparently with ODATSUKI MARU. At 1900, a surfaced enemy submarine is sighted in 28-10N, 122-00E and chased off.
28 October 1943:
Arrives at Takao.
3 November 1943:
Departs Takao and returns to port later that day.
8 November 1943:
At 1000, departs Takao with cable layer escort ODATE escorting convoy No. 217 consisting of Army tanker ICHIYO MARU, IJN shared (B/C-AK) ship TEISHO MARU (ex-German HAVENSTEIN), IJA transports KAZUURA, MATSUE, HAVRE (5652gt), KYOKUZAN MARUs, auxiliary transport KOSEI (2,170 GRT) MARU, tanker HORAI MARU and nine unidentified merchant ships. The convoy later splits into two parts.
11 November 1943:
Arrives with convoy No. 217 at the Yangtse River mouth. Departs there later that day with convoy No. 217.
13 November 1943:
The first part of convoy No. 217 arrives at Moji. KOSEI (2,170 GRT) MARU is detached before arrival and heads to Sasebo, arriving there later that day.
14 November 1943:
Arrives at Sasebo. The second part of the convoy No. 217 arrives at Moji later that day.
19 November 1943:
Departs Sasebo escorting convoy No. 115 consisting of consisting of ore carrier GYOKUREI, HIDA and GETSUYO MARUs, IJA transport LONDON MARU, IJN transports NIPPONKAI MARU and KOTO MARU No. 2 GO and IJA tanker OGURA MARU No. 1 and one unidentified merchant ship.
20 November 1943:
Arrives at Sasebo.
30 November 1943:
Departs Sasebo escorting a convoy.
1 December 1943:
Arrives at Moji.
2 December 1943:
Departs Moji escorting convoy No. 118 consisting of transports TATSUWA, DURBAN, KAIRYU, NANREI, NISSHU, PANAMA, RAIZAN, TACOMA, TSUKIKAWA MARUs, cargo JUICHISEI MARU (HOSHI MARU No. 11), tanker KONSAN MARU and three unidentified merchant ships.
3 December 1943:
At 1100, patrol boat PB-36 joins convoy No. 118 escort.
8 December 1943:
Arrives with the convoy at Takao.
26 December 1943:
Scheduled to temporarily escort two Sasebo bound convoys. Returns to Takao for convenience. Loads fried bean curd under Takao Guard District instruction No. 488.
28 December 1943:
Departs Takao escorting a convoy.
5 January 1944:
Arrives at Sasebo.
2 February 1944:
Arrives at Moji.
4 February 1944:
Departs Moji with destroyer MINEKAZE escorting convoy MOTA-01 consisting of tanker HOZAN (2,984 GRT), MALTA, SHINKOKU, TEIYU (ex-Italian CARIGNANO), TENSHIN and ZUIYO MARUs and an unidentified merchant ship.
10 February 1944:
At 0415, in position 23-12N, 121-30E MINEKAZE and MALTA MARU, the latter carrying 800 passengers, are torpedoed and sunk by LtCdr (later Rear Admiral-Ret) Ralph M. Metcalf's (USNA ’35) USS POGY SS-266). 99 sailors including her CO, LtCdr Imaizumi Masajiro (62) on MINEKAZE are KIA. 33 crewmen on MALTA MARU are KIA. SHINKOKU MARU is also damaged in the same attack and runs aground. CHOHAKUSAN MARU immediately begins an anti-submarine sweep.
11 February 1944:
At 1300, SHINKOKU MARU is refloated and later arrives at Takao.
13 February 1944:
Arrives at Takao.
14 February 1944:
TEIYU MARU arrives at Kirun, quickly departs there and later that day arrives at Takao.
17 February 1944:
Scheduled for an emergency transport run to the South Seas under military instruction No. 171935.
23 February 1944:
At 0600, departs Takao in convoy TAMO-05 consisting of CHIHAYA, CEYLON, NIPPO, SAN LUIS, FRANCE, PACIFIC, SHUNTEN, MUTSUYO (BOKUYO) and ASO MARUs also escorted by patrol boat PB-38, auxiliary subchaser TAMA MARU No. 7 and an unidentified warship.
27 February 1944:
Arrives at Sasebo.
6 March 1944:
Departs Sasebo.
7 March 1944:
Arrives at Shimonoseki.
12 March 1944:
Departs Shimonoseki.
13 March 1944:
Arrives at Kobe.
14 March 1944:
Departs Kobe.
16 March 1944:
Arrives at Yokohama.
20 March 1944:
Departs Yokohama.
20 March 1944:
Arrives at Kisarazu.
22 March 1944:
Departs Kisarazu with light cruiser YUBARI, DesDiv 5's HATAKAZE, DesDiv 6's IKAZUCHI and DesDiv 32's TAMANAMI, torpedo boat OTORI, kaibokan NOMI and HIRADO and subchasers CH-48, CH-54 and CH-51 escorting troop reinforcement convoy Higashi-Matsu No. 3 consisting of supply ship HAYASAKI and KOJUN, MEIRYU, TATSUURA, KENAN, TOMITSU, and NANYO MARUs, HOSHI MARU No. 11 (JUICHISEI) and NISSHO MARU No. 1. CHOHAKUSAN MARU escorts the east side of this convoy.
25 March 1944:
50 miles N of Muko Jima, Ogasawara Gunto (Bonins). LtCdr (later Rear Admiral-Ret) Bafford E. Lewellen's (USNA ‘31) old USS POLLACK (SS-180) attacks the convoy. USS POLLACK (SS-180) torpedoes and sinks CH-54 at 28-34N, 142-14E. Lewellen also claims damage to two freighters.
2 April 1944:
Arrives at Saipan.
E 3 April 1944:
Departs Saipan.
8 April 1944:
Arrives at Ssu Chiao Shan and briefly joins convoy MOTA-16 consisting of OGURA MARU No. 1, TACHIBANA, NITTETSU, YAMAKO (SANKO), HIROTA, TENSHIN, MITSU, TAKETSU (BUTSU), TOSHO, SHONAN and SHIRAHAMA MARUs also escorted by minesweeper W-18 and patrol boat PB-38. At 1054, the convoy departs there.
10 April 1944:
At 0700, detaches from convoy towards Kirun.
14 April 1944:
Arrives at Palau.
15 April 1944:
Scheduled for tactically assignment to the Maritime Defense under Takao Guard District instruction No. 16.
20 April 1944:
Departs Palau.
23 April 1944:
Arrives at Davao.
9 May 1944:
Departs Davao.
13 May 1944:
Arrives at Manila.
24 May 1944:
Departs Manila with destroyers HARUKAZE and ASAKAZE, kaibokan CD-11 and auxiliary gunboat TOMITSU MARU escorting convoy MATA-20 consisting of KUNIYAMA, FUKUJU, TAKETOYO, TENSHIN, CHINA, CHIHAYA, and EIYO MARUs.
28 May 1944:
Arrives at Takao with the convoy.
30 May 1944:
Scheduled for tactically assignment to the Southeast Sea Unit, Takao Defense Unit under Takao Guard District instruction No. 26.
3 June 1944:
Departs Takao and arrives later at Kirun.
4 June 1944:
Departs Kirun with destroyer SHIOKAZE and torpedo boat HATO escorting convoy MI-04 consisting of tankers CHIYODA, TAKETOYO, SHUNTEN and ZUIYO MARUs and transports TEIKA (ex-French CAP VARELLA) and PACIFIC MARUs.
11 June 1944:
At 0800, departs Takao with kaibokan KASADO, subchaser CH-58, auxiliary subchaser CHa-90 escorting convoy TAMA-20A consisting of 10 unidentified merchant ships.
12 June 1944:
Arrives at Takao where gunboat OKITSU joins convoy.
14 June 1944:
OKITSU detaches.
17 June 1944:
Arrives at Mutsure. Departs there later.
25 June 1944:
Arrives at Sasebo.
1 July 1944:
Departs Saei, Formosa (now Tsoying, Taiwan) with destroyer HASU and gunboat OKITSU escorting convoy No. 3311 consisting of KORYU, SETSUZAN (ex-Norwegian HELIOS), SHOZAN (ex-British CHEKIANG), DAICHI, FUKUEI, KAIKO (ex-British MARY MOLLER), NICHIZUI, PEKING, DAIKYU, YOKO and SHOHO MARUs and TOYO MARU No. 3.
4 July 1944:
At 0700, YOKO and DAIKYU MARUs are detached for Kirun. Later that day, SHOHO MARU develops engine trouble and falls behind.
6 July 1944:
At 0545, LtCdr (later Vice Admiral) Eli T. Reich's (USNA ’35) USS SEALION (SS-315) torpedoes and sinks SETSUZAN MARU (ex-Norwegian HELIOS) at 29-57N, 122-51E. One crewman is KIA.
10 July 1944:
Arrives at Sijiao Shan (Ssu Chiao Shan) anchorage near Shanghai. KORYU MARU probably rejoins the convoy at this point.
11 July 1944 Departs Sijiao Shan anchorage with the convoy.
19 July 1944:
Arrives at Seito (Tsingtao) with the convoy.
20 July 1944:
Departs Seito for anchorage off Haikou. Then heads via Wei Island, Koito Jima, Ikijima Gonoura to Sasebo.
24 July 1944:
Departs Sasebo for Imari Bay (near Moji).
26 July 1944:
Departs Imari Bay for Miri with kaibokan MATSUWA and CD-14, minesweeper W-18, auxiliary minesweeper TAKUNAN MARU No. 3, patrol boat PB-38, auxiliary patrol boats EIFU, FUYO, KASUGA and NUNOBIKI MARUs escorting convoy MI-13 consisting of tankers TEIKON, TOKUWA, KYOEI, SHINCHO, ATAGO MARUs and tanker OGURA MARU No. 2, and cargo ships HIYORI, DURBAN, KAZAN, KUNIYAMA, URAL, SHIROTAE, KOKUSEI, CHINA, HIGANE, MATSUURA, RISSHUN and ATLAS MARUs, and SHINSEI MARU No. 1.
27 July 1944:
IJA transport CHINA MARU suffers engine trouble and drops out of convoy. Auxiliary minesweeper TAKUNAN MARU No.3 escorts her back to Imari Bay.
28 July 1944:
While patroling her patrol area minelayer NIIZAKI meets up with the convoy.
29 July 1944:
MATSUURA MARU detaches and heads towards Kirun.
30 July 1944:
IJN oiler OGURA MARU No. 2 and minesweeper W-18 detach and head towards Port Saei, Formosa.
31 July 1944:
Arrives at Takao with the convoy, subsequently detaches.
5 August 1944:
Departs Takao.
20 August 1944:
Departs Takao escorting convoy TAMO-23. Arrives at Kirun later this day. At 0600, departs Kirun with kaibokan CD-6, CD-9 and CD-16 and subchaser CH-58 escorting convoy TAMO-23 consisting of auxiliary tanker HORAI and MATSUMOTO MARUs, cargo ships TETSUYO, SHINFUKU, NIKKO, KIYOKAWA MARUs, TONAN MARU No. 2 and seven unidentified merchant ships.
22 August 1944:
South China Sea. At 1955, LtCdr (later Admiral/CINCPACFLT) Bernard A. Clarey’s (USNA ’34) USS PINTADO (SS-387) torpedoes and sinks TONAN MARU No. 2 at 29-53N, 125-9E. Four crewmen are KIA.
26 August 1944:
Arrives at Moji with the convoy.
9 September 1944:
Departs Moji with torpedo boat SAGI, kaikoban ETOROFU, SHONAN, CD-6 and CD-16 escorting convoy MI-19 consisting of auxiliary tankers CHIHAYA, IWAKUNI, DAIMEI, EIHO, SAN DIEGO and MITSU MARUs and auxiliary transports DAIBIN (OTOSHI), KENZUI, ENOURA, MATSUURA, YULIN, HAKUSHIKA (HAKUROKU), ARISAN, TEIFU, TASMANIA , SHINSEI, DAIA, NIKKO and SHUNSHO MARUs.
10 September 1944:
At 1212, LtCdr (later Cdr) Edward E. Shelby's (USNA ’33) USS SUNFISH (SS-281) torpedoes and sinks CHIHAYA MARU at 33-49N, 127-41E. 76 troops, one gunner and eight crewmen are KIA. The convoy immediately retires to Chinto (Chin Hajo Island) where it regroups. The escorts launch a concerted, but unsuccessful attempt to find the submarine.
12 September 1944:
Departs Chinto with convoy MI-19.
16 September 1944:
At Yulin, Hainan Island. Kaibokan ETOROFU detaches and subsequently joins convoy HI-72/ MAMO-03 escort which suffered a series of devastating attacks in the South China Sea.
SHUNSHO, NIKKO, MATSUURA, ENOURA and KENZUI MARUs are detached that same day and head for Kirun escorted by kaibokan SHONAN, CD-6 and CD-16.
17 September 1944:
At 0800, CD-6 and CD-16 depart Kirun and meet up with the convoy.
18 September 1944:
Arrives at Takao with the rest of convoy MI-19 and subsequently detaches.
27 September 1944:
At 1330 departs Takao with kaibokan CD-1, CD-3, CD-7, target ship HAKACHI and auxiliary patrol boat OSEI MARU escorting convoy TAMO-26 consisting of NIKKO, SEISHIN, CLYDE, HAKUSAN, MATSUURA, DAIJO, GASSAN, YOKO and BIYO MARUs and SS-6 (Kidotei). CD-1 departs Saei at 1749 and joins the convoy.
28 September 1944:
Off Kirun, Formosa (now Keelung, Taiwan) CD-3 attacks an underwater contact. She drops 3 depth charges. Later this day auxiliary gunboat CHOHAKUSAN MARU arrives at Kirun with the convoy. Auxiliary patrol boat OSEI MARU detaches.
1 October 1944:
Departs Kirun with the convoy. At 0900 kaibokan CD-1 joins the convoy escort. Auxiliary gunboat CHOHAKASAN MARU detaches and heads towards Kirun to repair damage to her main cooling water pipe.
1 November 1944:
Navy (Resv) Lt Ishiwari Tadashi is confirmed as CO.
3 November 1944:
At 1000, departs Moji with kaibokan CD-23, CD-33, CD-51, CD-52 and CD-130 escorting convoy Mi-25 consisting of KACHOSAN, NIKKO, DAIA, DAITO, AKAGISAN, NICHIYO, KENSEI, HINAGA, TATSUTAMA, KINSEN and SHOEI MARUs, and tankers ATAGO, DAIRETSU, RYUSHO, GYOSHIN, DAISHU, DAIEI, OTSUSAN, OJIKASAN and YAMAMURA MARUs, YUZAN MARU No. 2 and one unidentified merchant ship.
5 November 1944:
Attached to General Escort Command Headquarters, 18th Escort Division.
8 November 1944:
KACHOSAN, KINSEN and NIKKO MARUs and the one unidentified merchant ship detach and head towards Kirun. AKAGISAN and NICHIYO MARUs detach and head towards Takao. OJIKASAN MARU develops engine problems and subsequently detaches and heads towards Mako. The rest of the convoy is diverted to Cape St. Jacques, French Indochina (now Vung Tau, Vietnam).
13 November 1944:
In the evening, anchors in Xuan Dai Bay, French Indochina at 13-22N, 109-17E off the coast with the rest of the convoy.
14 November 1944:
At 0800, departs Xuan Dai Bay with the convoy.
15 November 1944:
At 0100, about 10 nautical miles SE Cape Padaran, French Indochina, LtCdr Albert S. Fuhrman's (USNA '37) USS JACK (SS-259) torpedoes HINAGA MARU and YUZAN MARU No. 2 at 11-16N 108-54E. HINAGA MARU sinks. YUZAN MARU No. 2 runs aground and later becomes a total loss. On HINAGA MARU, 34 soldiers and one crewman are KIA and on YUZAN MARU No. 2, seven crewmen are KIA.
16 November 1944:
Arrives at St Jacques, with the convoy.
26 November 1944:
At 0200, departs Takao with CD-18 and kaibokan CD-26 escorting convoy TAMO-30 consisting of BANSHU MARU No. 32, HAKOZAKI MARU and three unidentified merchant ships. Calls at Kirun and departs there. At 2230, arrives and anchors in Hsiao An channel, S of Wenchow, China.
27 November 1944:
At 1730, departs Hsiao An channel.
3 December 1944:
Arrives with the convoy at Moji.
20 December 1944:
At Sasebo while drydocked seventeen Type 96 single 25mm MGs, sound detectors and electric probe equipment are fitted.
28 December 1944:
Attached to the Sasebo Naval District, Mine Unit under Sasebo Naval District instruction No. 162.
9 January 1945:
Mine Unit instruction No. 5:
Mine Unit CO conducts one emergency transport run to Nansei Shoto (Ryukyus) as soon as possible from 17 Jan ‘45 with his forces.
1 - There should be as many equipment transported as possible to outer Nansei Shoto Islands.
The 38th suicide attack motorboat Maru Re (Shinyo) squadron for Ishigakijima, 4 Kaiten squadrons for Okinawa, 30 Yokosuka MXY-7 ‘Ohka’ for Okinawa, 700 Type 93 mines and aviation fuel.
2 - The 951th Ku CO is to strictly monitor anti-submarine security for this transport unit.
12 January 1945:
Mine Unit instruction No. 9:
Minelayer KOEI MARU CO leads minelayers KOEI MARU and SAISHU, auxiliary gunboat CHOHAKUSAN MARU and kaibokan CD-22 and CD-29 on an emergency transport mission to Nansei Shoto Islands according to Mine Unit instruction No. 5.
18 January 1945:
Departs Sasebo with kaibokan CD-22 escorted by subchaser CH-58 and arrives at Tomie later this day.
20 January 1945:
Departs Tomie.
21 January 1945:
At 0740, at 29-00N, 126-24N subchaser CH-58 detects a submerged enemy submarine. ASW begins. At 0755, CH-58 drop 18 depth charges. At 0826, auxiliary gunboat CHOHAKUSAN MARU drops 14 depth charges. At 0908, CD-22 drops 15 depth charges. At 1030, ASW ends. At 1300, at 24-54N, 126-09E returns with kaibokan CD-22 and subchaser CH-58 to Tomie.
22 January 1945:
Arrives with CD-22 and CH-58 at Liu Hengshan , China.
23 January 1945:
Mine Unit instruction No. 8:
Deployment of transport units.
1 - Depending on the first transport unit consisting of minelayers KOEI MARU and SAISHU and kaibokan CD-29, resupply at Sasebo and continue mission.
2 - The second transport unit consisting of auxiliary gunboat CHOHAKUSAN MARU, kaibokan CD-22 and subchaser CH-58 resupplies at Kirun if needed. After resupplying return with sugar, alcohol and other local goods.
Mine Force instruction No. 3:
1 - First transport unit should continue its mission with immediate resupply at Sasebo if necessary.
2 - Second transport unit departs from its shelter after completion of scheduled mission and resupplies at Kirun if necessary.
24 January 1945:
Departs Liu Hengshan with kaibokan CD-22 and subchaser Ch-58.
25 January 1945:
Arrives at Taichow (now Taizhou) Islands, China with kaibokan CD-22 and subchaser Ch-58.
27 January 1945:
At 2220, at 27-05N, 123-45E kaibokan CD-22 drops 18 depth charges.
28 January 1945:
Arrives at Ishigaki with kaibokan CD-22 and subchaser Ch-58. Loads various goods.
29 January 1945:
Mine Force instruction No. 17:
1 - On 3 Feb ’45, minelayers NUWAJIMA and TSUBAME will become part of Mine Unit. Mine CO conducts transport to Nansei Shoto Islands.
2 - Early February: auxiliary gunboat CHOHAKUSAN MARU will transport 230 Type 94 mines to Okinawa, minelayer TSUBAME will transport 70 Type 94 mines to Ishigaki and minelayer NUWAJIMA will transport 70 Type 94 mines to Miyako. Minelayer KOEI MARU, and kaibokan CD-22 and CD-29 will transport the 44th suicide attack motorboat Maru Re (Shinyo) squadron and other goods to Oshima.
3 Mid February: After completing transport mission to Oshima, minelayer KOEI MARU will lay mine field No. 6 based on Kaigo Soden instruction No. 357 with the 18h Escort Division consisting of auxiliary gunboat CHOHAKUSAN MARU and one yet to be added escort ship.
4 While transporting Type 94 mines to Ishigaki and Miyako, auxiliary gunboat CHOHAKUSAN MARU and minelayers TSUBAME, NUWAJIMA and SAISHU will lay mines according to the layout plan commanded by Okine CO.
5 Late February: transport suicide attack motorboat Maru Re (Shinyo) squadrons and other specific items to Okinawa.
Departs Ishigaki that same day.
30 January 1945:
Arrives at Kirun. Loads ammunition.
2 February 1945:
At 0300, departs Kirun with kaibokan KURAHASHI and SHINNAN, CD-22 and subchasers CH-19 and CH-58 escorting convoy TAMO-40 consisting of MASASHIMA MARU and three unidentified merchant ships.
6 February 1945:
Arrives at Ssu Chiao Shan anchorage, Shushan (Chusan) Archipelago, China. Detaches there from the convoy.
8 February 1945:
Departs Ssu Chiao Shan anchorage and arrives later at Sasebo.
8 ~ 10 February 1945:
Loads approximately 1,000 mines and suicide attack motorboats Maru Re (Shinyo).
10 February 1945:
Departs Sasebo.
26 February 1945:
Arrives at Naha, Okinawa.
27 February 1945:
Departs Naha and arrives at Kin Bay, Okinawa that same day.
28 February 1945:
Departs Kin Bay and meets up with minelayers TSUBAME and NUWAJIMA, subchaser CH-49, kaibokan FUKUE and auxiliary subchasers CHa-200 and SANGYO MARU escorting convoy SAI-01 consisting of DAIKEN, TOYOSAKA, EDOGAWA, KOSHU and NICHIRIN MARUs. Arrives at Naha later in the day and detaches from the convoy.
1 March 1945:
Detaches and arrives at Naha. Hit by 6 bombs from USN TF-58 carrier based aircraft and sunk. Two Type 96 twin 25mm MGs remain above water and remain operational.
(CHOHAKUSAN MARU wreck, postwar – Berend Van der Wal collection)

(CHOHAKUSAN MARU wreck MGs, postwar – Berend Van der Wal collection)

10 May 1945:
Removed from the Navy’s list under instruction No. 417.
November 1997 ~ July 2006:
During the Naha airport undersea tunnel construction, the CHOHAKUSAN MARU wreck is discovered on the projected location of the tunnel. The wreck is moved to another location.
3 August 2019:
The wreck of the CHOHAKUSAN MARU is rediscovered on its new location.

(CHOHAKUSAN MARU wreck, 3 Aug ‘19 – Berend Van der Wal collection)

Authors' Notes:
[1] Also known as CHOHAKUZAN MARU.
[2] NRT is a ship's cargo volume capacity expressed in "register tons", one of which equals to a volume of 100 cubic feet (2.83 m3). It is calculated by subtracting non-revenue-earning spaces i.e. spaces not available for carrying cargo, for example engine rooms, fuel tanks and crew quarters, from the ship's gross register tonnage (GRT). Net register tonnage (NRT) is not a measure of the weight of the ship or its cargo, and should not be confused with terms such as deadweight tonnage or displacement.
[3] Army transport LISBON MARU was heavily damaged after having hit a Japanese defensive mine off Mako Harbor on 2 Feb ’42.
[4] TEISON MARU (ex-French VILLE DE VERDUN) was torpedoed that same day by LtCdr Jesse L. Hull’s (USNA ’26) USS FINBACK (SS-230). No casualties were sustained but ship was abandoned and after having drifted for three days, sank at 25-20N, 121-01E.
[5] AFRICA MARU was torpedoed that same day by LtCdr Jesse L. Hull’s (USNA ’26) USS FINBACK (SS-230). Ship sank the following day at 24-26N, 120-26E taking with her three crewmen.
Thanks go to Gengoro S. Toda of Japan.

- Gilbert Casse, Berend van der Wal and Peter Cundall.

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