© 2006-2016 Bob Hackett, Sander Kingsepp and Peter Cundall
7 September 1944:
Tamano. Laid down as Yard No. 414 at Mitsui Engineering & Shipbuilding’s yard.
5 October 1944:
Named OJIKA. 
7 December 1944:
Fitting-out office is established.
30 December 1944:
15 January 1945:
Fitting-out chief officer Reserve LtCdr Isobe Teruyoshi arrives at his post.
20 January 1945:
Fitting-out personnel chief engineer Reserve Lt Yabushita Tatsugoro and navigation officer Reserve Lt Sato Motoo
arrive at their posts.
21 February 1945:
Completed and registered in the Sasebo Naval District and assigned to the anti-sub training force of
the Kure Guard Unit. LtCdr Isobe is the Commanding Officer. Departs the same day for Kure. Conducts workup and training.
1 March 1945:
OJIKA arrives at Saeki.
28 March 1945:
ComKure Guard Unit's Rear Admiral Kiyota Takahiko (42) dispatches the 1st, 2nd and 3rd Sweeping Units to conduct an offensive sweep
in the Hyuga Nada and Osumi Channel to provide anti-submarine cover for the planned sortie of battleship YAMATO and her escorts. The
surface units are supported by eight Magnetic Anomaly Detector (MAD) equipped Aichi E13A1 Jakes and Kyushu Q1W1 Lornas from the Saeki
Naval Air Group.
After departing Saeki on this morning, the 3rd Sweeping Unit consisting of kaibokan CD-59 (flagship), CD-65, OJIKA and MOKUTO starts
sweeping from a point south of Mizunoko-shima Lighthouse, Bungo Strait and then proceeds southward. The four kaibokan sail in parallel
formation with CD-65 being the left end ship. Distance between the ships is 3 to 4 nautical miles and all four kaibokan are zig-zagging on
their way south, base course 180 degrees. At 1027, one of the ASW Aichi E13A1 detects a contact and directs the 3rd Sweeping
Unit to that area. At about noon, MIKURA and CD-33, which are detached from the 1st Surface Escort Fleet and coming directly from
Moji, join the 3rd Sweeping Unit about 15 nm E of Hososhima, Miyazaki Prefecture. MIKURA and CD-33 sail in a single row formation and take
position 1,000 meters to the port side of CD-65.
At about 1300, CD-65 recognizes two exhaust fumes near the position reported by the Aichi E13A1, at 32-10N, 131-50E. CD-65, CD-59,
OJIKA and MOKUTO prepare for depth charge battle while MIKURA and CD-33 continue southward. Shortly afterwards the four kaibokan
conduct several attacks on a submarine contact with Type 3 streamlined depth-charges. After a heavy depth charge attack by CD-59 a
large amount of oil and debris is sighted in the area of 32-16N, 132-05E. CD-59 claims a certain kill. The intensive depth charging
is heard by SILVERSIDES (SS-236), SEA DOG (SS-401), HACKELBACK (SS-295) and THREADFIN (SS-410) operating in adjacent waters. 
Thereafter, news arrive on enemy air and submarine attacks and the force withdrew to the north. On the evening, temporarily anchors
in Funakoshi Bay, NW side of Sukumo Bay.
29 March 1945:
The four kaibokan depart Funakoshi Bay and later this day arrive at Saeki. Due to serious enemy minelaying activities and air attacks
it is decided to transfer a part of the anti-sub training force consisting of 10 kaibokan from Saeki to Maizuru. The other kaibokan
are to proceed to Kure. Rear Admiral Nishioka Shigeyasu, CO of the anti-sub training force, transfers his flag from KOGANE MARU
(1905 grt) to OJIKA.
5 April 1945:
Reassigned to the General Escorts´s Command 1st Escort Fleet. The same day OJIKA and CD-59 arrive at Saeki.
Both vessels receive order to co-operate with the Kure Guard Unit for sweeping sea lanes ahead of planned sortie of battleship YAMATO
and her escorts.
6 April 1945:
OJIKA and CD-59 depart Saeki for the Tokuyama Oil Depot. After refuelling both vessels are sweeping ahead of battleship YAMATO and
25 April 1945:
OJIKA arrives at Moji.
26 April 1945:
OJIKA is reassigned to the 1st Escort Fleet´s 103rd Escort Squadron.
28 April 1945:
At 0600, OJIKA departs Moji for Shanghai with kaibokan INAGI and CD-59 escorting convoy MOSHI-05 consisting
of MIHO MARU. MIHO MARU has loaded at Kure and Moji 153 passengers (including military passengers and a number of women), arms,
ammunition and ca. 2.300 tons of war supplies as well as 3 Daihatsu landing barges as deck load. In the afternoon, the convoy passes
2 nm N off Mitsu-Shima Lighthouse (34-43-26N, 129-26-38E), N-tip of Tsuhima. At 2000, the convoy anchors at Tozo Bay (Tojang-p´o)
(34-45N, 128-41E), SE coast of Kyosai Island (Koje-do), S of Chinkai (Chinhae), South Korea.
29 April 1945:
At 0500, convoy weighs anchor and proceeds westward. At 2000, anchors south of Kasa Island (Kasa-do)
34-28N, 126-03E) in the Chochiku Channel (Changchuk-sudo).
30 April 1945:
At 0200, the convoy weighs anchor and departs, course 279. Several hours later passes through Maikotsu
Channel (Maemul-sudo), north of Santai Island (Samt´ae-do) (34-26N, 125-17E). Since leaving Kasa Island the weather has deteriorated
considerably. As there is indication of a nearby enemy sub, OJIKA separates from the convoy at ca. 1000 to scare away any lurking
enemy submarine. At noon it starts raining and a strong wind is blowing with 10 m/s. Due to poor visibility INAGI and CD-59
temporarily loses sight of MIHO MARU.
At about 1400, a lookout on MIHO MARU´s stern recognizes the returning OJIKA. Suddenly, immediately after sighting OJIKA, the lookout
discovers a half-submerged conning tower of a trailing enemy submarine and four approaching torpedo tracks at the same time. MIHO
MARU at once blows her steam whistle to notify the escorts and at the same time order is given [right – full rudder, maximum speed.
but is it already too late.
At about 1408, LtCdr Allen R. Faut´s USS TREPANG SS-412) torpedoes MIHO MARU at 34-19N, 124-03E. MIHO MARU is hit by two torpedoes
portside at Nos. 2 and 3 holds. Both holds are heavily flooded and the inrushing water also reaches the engine room. The ship
develops a 15 degree list to starboard. The three kaibokan counter-attack and drop 27 depth charges. MIHO MARU´s anti-damage control
is very effective and by 1440 the ship has escaped from immediate danger of sinking. Captain Nakahara Renji orders evacuation of all
passengers who are transferred to INAGI and CD-59. By 1930, all passengers and crew have abandoned MIHO MARU. 14 crew, 26 armed guards
and 94 passenger including several women are missing.
At about 2130, USS TREPANG finally seals MIHO MARU´s fate by sinking the drifting wreck with four further torpedoes. MIHO MARU
disappears beneath the waves about 70 nm WSW of Ko Island (Hong-do), 34-27N, 123-48E. NB: On 4 May 1945, INAGI and CD-59 land MIHO
MARU´s survivors at Shanghai where the heavily wounded are taken to the naval hospital while the others are brought
to the naval barracks.
1 May 1945:
At 1300, OJIKA reports her position as 33-20N, 122-15E, course 040, speed 14 knots.
2 May 1945:
Yellow Sea. At 2310, LtCdr Russell Kefauver´s USS SPRINGER (SS-414) attacks an 800 ton escort vessel. Kefauver fires a spread of four torpedoes.
SPRINGER´s crew hears the first explode and then see and hear two more hits which sink OJIKA about 108 nm W of Shokokusan Island
(Sohuksan-do), at 33-56N, 122-49E. From a distance, crew members on board kaibokan CD-59 observe two columns of fire ascending from
OJIKA´s portside fore and aftship. OJIKA is lost with her entire crew of 226 including LtCdr Isobe.
3 May 1945:
At 1014, USN codebreakers intercept and decrypt a message that reads: “Summary of disaster to OJIKA: OJIKA and CD-59 were on station abeam this ship distant 1.5 kilometers proceeding on course 240 degrees. ----about 5 minutes after CD-59 had picked up something resembling an enemy submarine and was observing it, OJIKA was seen to open fire. A few seconds later there was an explosion and a pillar of fire --- and sank. At 0930, oil and debris were seen to the northeast of the disaster ---.”
At 1212, codebreakers decrypt a message from minesweeper W-20 that reads: “Am heading to the scene of the OJIKA disaster ---.”
Yellow Sea. 140 miles SE of Mokpo, Korea. CD-25 is proceeding to the scene of the sinking of OJIKA. At about 2300, Kefauver’s
SPRINGER makes a night surface radar attack on CD-25. Kefauver fires six torpedoes and claims three hits on the small escort. CD-25
capsizes and sinks at 33-56N, 122-49E.
5 May 1945:
Yellow Sea. 140 miles SE of Mokpo, Korea. W-20 is proceeding to the scene of the sinking of OJIKA, but W-20 is
intercepted enroute by LtCdr Allen R. Faust's USS TREPANG (SS-412) that torpedoes and sinks her at 33-56N, 122-49E.
7 May 1945:
At 1915, codebreakers decrypt a message sent earlier by W-20 regarding the event of 3 May that reads:“In accordance with Yellow Sea
Area Force OpOrd No. 39, CD-25 and W-20 left the vicinity of Shichihatsu Shima the morning of the 3rd to proceed to the scene of the torpedoing of OJIKA .”
8 May 1945:
At 0515, codebreakers decrypt a message from the CO of the 103 Division: “Hoisted flag in OKI and sortied from Niioshima to carry out
search for CD-25 and W-20 and to sweep for enemy submarine.”
The Yellow Sea Area Escort Force presumes CD-25 and W-20 were lost with all hands.
25 May 1945:
Removed from the Navy List.
 OJIKA was also known as OGA. The first Japanese character O can be read as Otoko, Dan or Nan and the suffix Roku can be read also as Shika (Jika) or more commonly Ka or Ga. So either is possible.
 If, in fact, a submarine was lost to these attacks it may have been Cdr David R. Connole's veteran USS TRIGGER (SS-237). Alternatively, TRIGGER may have fallen victim to a mine. There has been no official determination on
the cause, or even the location, of her loss.
Thanks go to the John Whitman for info on CNO intercepts of Japanese messages. Thanks also go to Erich Muethlthaler of Germany for a major rewrite of the TROM in the revision 2.
-Bob Hackett, Sander Kingsepp and Peter Cundall