© 2007-2017 Bob Hackett, Sander Kingsepp and Peter Cundall
20 March 1944:
Laid down at Fujinagata Shipbuilding.
15 November 1944:
Launched and numbered CD-40.
22 December 1944:
Completed and registered in the IJN.
5 January 1945:
Departs Kagoshima in unknown convoy with escort consisting of kaibokan CD-30, CD-40, sub-chaser CH-49, minesweeper W-15, auxiliary netlayer SHINTO MARU No.2, auxiliary minesweepers CHITOSE MARU and TAIHEI MARU No.3 GO and auxiliary patrol boat CHOUN MARU No.13.
10 January 1945:
East China Sea. At about 0400, LtCdr (later Cdr) Carl R. Dwyer's (USNA ’38) USS PUFFER (SS-268) attacks an unidentified convoy. Dwyer torpedoes and sinks escort CD-42 with all 170 hands including her CO, LtCdr Egashira Tomiya, then torpedoes and damages CD-30 at 26-45N, 126-11E. CD-30's bow and bridge are wrecked by the torpedo, but she manages to steam to Okinawa at 5 knots. CD-30 has five sailors KIA. En route to Naha, Okinawa, she is further attacked by an unidentified submarine which missed CD-30 with a salvo of four torpedoes.
1 February 1945:
CD-40 is assigned to the General Escort Command's First Escort Fleet.
5 February 1945:
At 0700, CD-40 departs Moji for Hong Kong with kaibokan CD-69 and subchaser CH-21 escorting convoy MOHO-02. The convoy consists of MIHO, KINSEN, PEKING and BANSAI MARUs. The convoy sails via the Korean coast stopping at Jinsen.
9 February 1945:
At 1915, anchors at Chusan (Shoushan) Island.
10 February 1945:
Departs the anchorage. Later briefly stops at Amoy.
14 February 1945:
At 1100, arrives at Hong Kong.
20 February 1945:
At 1600 departs Hong Kong in convoy HOMO-02 consisting of MEISEI and TENSHO MARUs and five unidentified merchant ships also escorted by kaibokan AGUNI.
3 March 1945:
At 1730 arrives at Moji. Transfers to Mitsubishi Zosen's Hikoshima yard and undergoes repairs.
12 March 1945:
At 1745 departs Hikoshima and at 1900 arrives at Mutsure.
15 March 1945:
At 0640 departs Mutsure and at 0900 arrive at Moji.
16 March 1945:
At 0900, CD-40 departs Moji for Keelung with kaibokan CHIKUBU, CD-102 and CD-106 escorting convoy MOTA-43. The convoy consists of transports KIYOKAWA, HAKOZAKI, TATSUHARU and NIKKO MARUs.
17 March 1945:
At 1642 the convoy anchores off Hikin To (Pigum Do).
18 March 1945:
At 0554 departs Hikin To.
19 March 1945:
225 miles NNE of Shanghai. At 0258, at 33-07N, 122-05E, LtCdr (later Cdr) Robert K. Worthington's (USNA ’38) USS BALAO (SS-285) attacks the convoy and torpedoes TATSUHARU and HAKOZAKI MARUs. Another torpedo just misses CD-40. HAKOZAKI MARU is torn apart by internal explosions as her cargo of gasoline, shells and torpedoes ignites and blows off her stern. She quickly sinks, but her forward section stays afloat blazing until finally sinking at 0320. The combination of fire, explosions and 5 degree centigrade water means that almost all aboard perish. 928 passengers, 51 gunners and 139 crewmen, a total of 1,118 are
The torpedo strike on TATSUHARU MARU kills 149 military personnel, but the ship remains afloat and later makes Shanghai. CD-102 and CHIKUBU launch an unsuccessful depth charge counter-attack on USS BALAO, then rescue 130 survivors. Meanwhile at 1933 CD-106 arrives at Ssu Chiao Shan escorting NIKKO and KIYOKAWA MARUs.
21 March 1945:
At 0800 the other escorts arrives at Ssu Chiao Shan.
At 1145, USN codebreakers intercept and decrypt a message from CD-40 that reads: “Sighted one enemy 4-engine plane position 26-55N, 120-20E.” Then at 1200, codebreakers decrypt a message from CD-40 that reads: “Under bombing attack in position 26-58 N, 120-29E.”
22 March 1945:
At 0300 departs Ssu Chiao Shan.
23 March 1945:
At 1825 arrives at Mazu Shan and departs later that day.
24 March 1945:
At 1603 arrives at Fuyan Tao.
25 March 1945:
At 1600 departs Fuyan Tao.
26 March 1945:
At 1700 arrives at Kirun.
28 March 1945:
Off Keelung, Formosa. CD-102 and CD-106 are damaged by near-misses of bombs from USAAF B-24 "Liberators" at 26-58N, 120-29E, but CD-40 escapes undamaged.
1 April 1945:
At 0615, CD-40 departs Keelung for Moji with kaibokan CHIKUBU, CD-102, and CD-106 escorting convoy TAMO-53 consisting of the survivors of convoy MOTA-43, NIKKO and KIYOKAWA MARUs. Both merchant ships are loaded with sugar needed for conversion to aviation fuel and butane and evacuees from Formosa, mostly women and children.
9 April 1945:
Yellow Sea. LtCdr (later Captain/MOH) George L. Street III’s (USNA ’37) USS TIRANTE (SS-420), alerted by an “Ultra” signal based on code-breaker’s intelligence, stalks convoy TAMO-53 enroute from Shanghai to Japan. Street fires
three Mark 18-2 electric torpedoes at each of two targets at 36-50N, 123-55E. One spread misses, but the other hits NIKKO MARU in the bow and engine room. She sinks taking down 563 passengers, 14 gunners, 16 guard force soldiers, two
signalers and 73 crewmen.
The convoy’s escorts counter-attack USS TIRANTE. Street fires a Mark-27 “Cutie"acoustic homing torpedo at CD-102. USS TIRANTE’s crew hears "breaking-up" noises, but the kaibokan does not sink. CD-102 loses seven men blown off the fantail when the Cutie hits. CHIKUBU tows damaged CD-102 to safety and rescues some of NIKKO MARU's survivors. CD-40 and the remainder of the convoy head for Moji.
13 April 1945:
Off Futaio Jima. CD-40 is damaged by a mine laid by B-29 "Super Fortresses" of USAAF's 20th Bomber Command. Later that day, TAMO-53 arrives at Moji.
20 April 1945:
CD-40 is reassigned to the Maizuru Naval District. Undergoes repairs.
20 May 1945:
Repairs completed, CD-40 departs Maizuru.
22 May 1945:
Arrives at Fushiki and remains there the rest of the month.
10 July 1945:
Reassigned to the First Escort Fleet's 105th Escort Squadron.
15 August 1945:
CD-40’s crew is notified of the termination of the war.
30 November 1945:
Removed from the Navy List.
1 December 1945:
Assigned to mine sweeping duties by the Allied Occupation Force. 
29 August 1947:
Tsingtao, China. Ceded to the Republic of China as a war reparation. Renamed CHAN AN.
 In 1945, the U. S. Army Air Force launched a five-phased campaign known as “Operation Starvation” to mine Japan’s home waters. The USAAF used 80 to 100 B-29 “Super Fortress” heavy bombers of the 21st Bomber Command based at Tinian in the Marianas. The B-29s could carry seven 2,000 lb. or twelve 1,000 lb. mines.
Beginning on 27 March 1945 and continuing until 5 August 1945, the B-29s flew 1,529 nighttime radar sorties and laid 4,900 magnetic, 3,500 acoustic, 2,900 pressure and 700 low-frequency mines for a total of more than 12,000 mines laid in Japanese waters. These mines sank 294 ships, damaged 137 beyond repair and damaged another 239 that could be repaired. The total was 1, 250,000 tons sunk or damaged or about 75 percent of Japanese shipping available in March 1945. Only 15 B-29s were lost during the mining campaign.
Postwar, removal of these mines posed a major challenge for the Allied Occupation Forces. They pressed 269 Japanese ships of various types into mine sweeping service to augment their own efforts.
Thanks go to Dr. Higuchi Tatsuhiro of Japan and to Mr. Gilbert Casse of France. Thanks also go to the late John Whitman of Virginia, USA for info on CNO intercepts of Japanese messages.
-Bob Hackett, Sander Kingsepp and Peter Cundall