SENSUIKAN!

© 2002 Bob Hackett & Sander Kingsepp

27 September 1941:
The I-23 is completed at the Yokosuka Navy Yard, commissioned in the IJN and based in the Yokosuka Naval District. LtCdr Shibata Genichi is assigned as the Commanding Officer.

20 November 1941: Operation "Z":
The I-23 is in Rear Admiral Sato Tsutomu's SubRon 1 in Captain (later Rear Admiral) Sasaki Hankyu's SubDiv 3 with the I-21 and the I-22. Departs Yokosuka with the I-19.

23 November 1941:
Arrives at Hitokappu Bay, Etorofu in the Kuriles.

26 November 1941:
Departs Hitokappu for the Hawaiian Islands.

27 November 1941:
En route, the I-23, -19 and the I-21 refuel from a fleet oiler.

1 December 1941:
The I-23 lags behind the main group after losing one shaft as a result of diesel trouble.

2 December 1941:
The coded signal "Niitakayama nobore (Climb Mt. Niitaka) 1208" is received from the Combined Fleet's flagship, the NAGATO. It signifies that hostilities will commence on 8 December (Japan time). Mt. Niitaka, located in Formosa is the highest point in the Japanese Empire.

7 December 1941: The Attack on Pearl Harbor:
The I-23 is stationed N of Hawaii.

13 December 1941:
The I-23 heads for the West Coast of the United States.

20 December 1941:
20 miles off Monterey Bay, California. The I-23 fires eight or nine shells at the 6,771-ton Richfield Oil Company tanker AGWIWORLD but misses the zigzagging AGWIWORLD and she escapes to safety.

24 December 1941:
Off Monterey. The I-23's lookouts sight a ship that at first they identify as an old gunboat, but later recognize as a steamship. The I-23 then shells and damages the 2,119-ton American steamship DOROTHY PHILLIPS' rudder and she runs aground.

January 1942: Operation "K-1" - Flying Boat Attack on Pearl Harbor:
The Naval General Staff develops a plan to raid Pearl Harbor using two large Type 2 four-engined H8K1 "Emily" flying boats. The objective of the attack is to disrupt ship repair activities. The plan calls for the planes to depart Wotje in the Marshalls and fly to French Frigate Shoal in the Hawaiian Islands (500 miles WNW of Pearl Harbor) where they are to be refueled by I-class submarines.

11 January 1942:
Arrives at Kwajalein.

1 February 1942: American Air Raid on Kwajalein:
Vice Admiral (later Fleet Admiral) William F. Halsey Jr's Task Force 8 (USS ENTERPRISE (CV-6) raids Kwajalein and Wotje in the Marshall Islands. The ENTERPRISE's Douglas "Dauntless" SBDs of VB 6 and VS 6 and TBD "Devastators" of VT 6 sink a transport and damage the light cruiser KATORI, flagship of the Sixth Fleet's (Submarines) Commander, Vice Admiral Shimizu Mitsumi (former CO of ISE). The submarine depot ship YASUKUNI MARU and several other important ships are also damaged in the raid.

The I-23 is anchored at the port side of the I-26 which also does not dive. The I-23 is strafed by Devastators of VT-6 that kill a sailor and puncture one of her fuel tanks. Various supplies stacked on her upper deck catch fire, but another Devastator straddles her stern with bombs that douse the fire. By the time the Dauntlesses of VS-6 and VB-6 arrive, all the submarines have submerged. Most of the supplies on their decks are lost.

The I-23's ruptured fuel tank is hastily repaired, but she still leaves an oil slick when departing Kwajalein later with other submarines in an unsuccessful pursuit of Halsey's Task Force.

5 February 1942: Operation "K-1" - The Second Air Attack on Pearl Harbor:
At Kwajalein. Five submarines are selected to participate in Operation K-1, the planned second air attack on Pearl Harbor. The objective of the attack is to bomb the "Ten-Ten Dock" and disrupt ship repair activities. The I-9 is assigned to take up station midway between Wotje and the Shoal and act as a radio beacon for two Kawanishi H8K1 "Emily" flying boat bombers. The I-19, I-15 and the I-26 are to refuel the flying boats at the Shoal. The I-23 is to standby 10 miles south of Pearl Harbor, provide weather reports and act in an air-sea rescue capacity. The submarines depart for their stations.

8 February 1942:
On a reconnaissance mission.

14 February 1942:
The I-23 reports her position as south of Oahu, Hawaii. She is not heard from again.

28 February 1942:
Presumed lost with all 96 hands off Hawaii.

30 April 1942:
Removed from the Navy List.

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Authors' Note:
Special thanks for help in preparing this TROM go to Dr. Higuchi Tatsuhiro of Japan. – Bob Hackett and Sander Kingsepp.

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