(Type B1 submarine - colorized photo by Irootoko Jr)
IJN Submarine I-23: Tabular Record of
© 2002-2016 Bob Hackett & Sander Kingsepp Revision 2
8 December 1938:
Laid down at Yokosuka Navy Yard as Submarine No. 41.
24 November 1939:
15 March 1941:
Cdr (Captain, posthumously) Sano Takao (50)(the
current CO of I-70) is appointed Chief Equipping Officer.
31 March 1941:
LtCdr (Captain, posthumously) Inoue Norikane (51)
(the current CO of I-75) is appointed Chief Equipping Officer.
15 May 1941:
LtCdr (Captain, posthumously) Shibata Genichi (51)
(former CO of I-54) is appointed Chief Equipping Officer.
27 September 1941:
Yokosuka Navy Yard. I-23 is completed and
registered in the IJN. Attached to Yokosuka Naval District. Assigned to Captain
(later Rear Admiral) Sasaki Hankyu's SubDiv 3 in Rear Admiral Sato Tsutomu's
SubRon 1 with I-21 and I-22. LtCdr Shibata is the Commanding Officer.
1 October 1941:
Departs Yokosuka for Saeki Bay for a training cruise
carrying a Watanabe E9W1 Type 96 "Slim" floatplane. Carries out floatplane
launch tests at sea.
Late October 1941:
Prior to return to Yokosuka I-23 makes a brief
stop at Kobe.
Early November 1941:
Dry-docked at Yokosuka Navy Yard. The floatplane
is debarked; its pilot, CPO Fujita Nobuo is transferred to I-25. An additional
avgas tank is fitted abaft the conning tower to refuel large seaplanes at sea.
17 November 1941:
Receives the order to embark food, provisions and
armament for another "training cruise."
20 November 1941: Operation "Z":
At 0400, departs Yokosuka.
23 November 1941:
Arrives at Hitokappu Bay, Etorofu in the Kuriles.
26 November 1941:
Departs Hitokappu for the Hawaiian Islands with a
three-strong Patrol Unit (I-19, I-21 and I-23), assigned to the patrol ahead of
Nagumo's Carrier Striking Force.
27 November 1941:
En route, I-23, I-19 and I-21 refuel from a fleet
30 November 1941:
I-23 lags behind the main group after losing one
shaft as a result of the starboard diesel trouble.
2 December 1941:
The coded signal "Niitakayama nobore (Climb Mt.
Niitaka) 1208" is received from the Combined Fleet's flagship, 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.
6 December 1941:
Around 1500 rejoins the Carrier Striking Force.
Exchanges signals with carrier AKAGI.
7 December 1941: The Attack on Pearl Harbor:
Sails with the Carrier
Striking Force. At 1510, I-23 is reassigned to the Advance Force and ordered
to proceed to an area N of Hawaii.
9 December 1941:
I-6 reports sighting a LEXINGTON-class aircraft
carrier and two cruisers off Oahu, heading ENE. Vice Admiral Shimizu in KATORI
at Kwajalein orders all of SubRon 1's boats, except the Special Attack Force,
to pursue and sink the carrier.
I-23, now patrolling S of Kauai Island, Hawaii, joins the chase.
10 December 1941:
While proceeding surfaced, I-23's lookouts report
sighting a patrol plane. After crash-diving, I-23 accidentally descends to the
depth of 390 ft.
11 December 1941:
Redirected to the West Coast of the United States to
raid American shipping in the Monterey Bay area.
18 December 1941:
Arrives within 100 miles from the West Coast.
19 December 1941:
Off Monterey Bay. At 1800, the submerged I-23
sights an unescorted old type cruiser with three funnels on a southerly course.
While preparing for a torpedo attack, the contact is lost.
20 December 1941:
20 miles off Cypress Point, Monterey Peninsula,
California. After 1415, I-23 battle-surfaces on the Richfield Oil Company's
6,771-ton tanker AGWIWORLD at 37N, 122W, firing a total of 14 shells, but misses
the zigzagging target in rough seas. AGWIWORLD escapes to safety.
22 December 1941:
Departs the West Coast for the Palmyra Island area.
23 December 1941:
I-23 is attacked and bombed by a four-engined patrol
aircraft, but manages to dive away and receives no damage.
26 December 1941:
After sundown, LtCdr Shibata sights the lights of
an enemy vessel. I-23 chases it for an hour, but is forced to dive away after an
enemy patrol aircraft appears.
28 December 1941:
I-23 is briefly chased by a flight of three patrol
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.
1 January 1942:
After sundown I-23 attempts to conduct periscope
reconnaissance of Palmyra Island, but comes under gunfire from ashore. LtCdr
Shibata decides to withdraw within 20 miles from the island and make another try
2 January 1942:
I-23's recce mission is canceled. She is redirected
to an area betwen Hawaii and the Fiji Islands.
3 January 1942:
Arrives at the assigned area.
5 January 1942:
Departs for 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. ENTERPRISE's Douglas "Dauntless"
SBDs of VB-6 and VS-6 and TBD "Devastators" of VT-6 sink a transport and damage
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.
Anchored between tender YASUKUNI MARU and I-26, I-23 is embarking sea
stores. She returns fire while her sailors attempt to dump the deck cargo
overboard. When YASUKUNI MARU receives a bomb hit, one of the 25-mm AA gunners
aboard I-23 is injured by bomb fragments. Her floatplane avgas tank ignites at
the same time, causing a small fire.
By the time the Dauntlesses of VS-6 and VB-6 arrive, all submarines
have submerged. After the attack I-23 briefly participates in an unsuccessful
pursuit of Halsey's Task Force, then returns to Kwajalein.
5 February 1942: Operation "K-1" - The Second Air Attack on Pearl
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. 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. I-19, I-15 and
I-26 are to refuel the flying boats at the Shoal. I-23 is to standby at Point N
(SSW of Keahole Point, Hawaii), provide weather reports and act in an air-sea
rescue capacity. The submarines depart for their stations.
8 February 1942:
I-23 reports that she has arrived within 200 miles S
14 February 1942:
I-23 reports her position as south of Oahu, Hawaii.
24 February 1942:
At 2330 (JST), I-23 transmits her sixth and last
report from the Hawaii area.
28 February 1942:
Presumed lost with all 96 hands off Hawaii,
including the Combined Fleet staff officer Lt Konishi Masayoshi.
30 April 1942:
Removed from the Navy List.
 According to an entry from a recently published I-23
sailor's wartime diary, her E9W1 floatplane conducted a reconnaissance flight
over Pearl Harbor around 8 December. However, this episode is refuted by
several first-hand accounts, not to mention the diary of I-23's engineering
officer, Lt Kanamori Sueo, that covers the same time span. Considering that the
floatplane had been debarked prior to the sortie, the I-23 recce flight story
appears to be apocryphal.
 Several sources credit I-23 with attacking the 2,119-ton steamer
DOROTHY PHILLIPS on 24 December 1941. Considering that I-23 had left that area
already, this must be a mistake.
 Over the years many theories have been advanced about the loss of
I-23, but no supporting evidence has been found. A diving accident as suggested
by authors Boyd and Yoshida still remains the most likely explanation.
Thanks go to Dr. Higuchi Tatsuhiro of Japan.
– Bob Hackett and Sander Kingsepp.
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