(Type B1 submarine - colorized photo by Irootoko Jr)
IJN Submarine I-15: Tabular Record of
© 2001-2016 Bob Hackett & Sander Kingsepp
25 January 1938:
Laid down at Kure Navy Yard as Submarine No.
37, the lead boat of the new B-1 class.
7 March 1939:
Launched as I-15.
1 December 1939:
Cdr (later Captain) Oyama Toyojiro (47)(former CO of
I-6) is appointed the Chief Equipping Officer (CEO).
30 September 1940:
Kure. I-15 is completed, registered in the IJN and
attached to Yokosuka Naval District. Cdr Oyama Toyojiro is the CO.
15 November 1940:
I-15 is assigned to Vice Admiral Shimizu Mitsumi's
(former CO of ISE) Sixth Fleet's Advance Expeditionary Fleet in Sixth Fleet
(Submarines) under Rear Admiral Sato Tsutomu's (former CO of FUSO) SubRon 1 in
Captain Imazato Hiroshi's SubDiv 1 with I-16.
20 December 1940:
Cdr (Captain, posthumously) Ishikawa Nobuo (49)
(former CO of I-124) is appointed the CO.
21 November 1941: Operation "Z":
I-15 is in SubRon 1, SubDiv 1,
Advance Force. She departs Yokosuka for the Hawaiian Islands with Captain
Imazato embarked on her first war patrol.
2 December 1941:
The coded signal "Niitakayama nobore (Climb Mt.
Niitaka) 1208" is received from the Combined Fleet. It signifies that
hostilities will commence on 8 December (Japan time). Mt. Niitaka, located in
Formosa (now Taiwan), is then the highest point in the Japanese Empire.
7 December 1941: Operation "Z" - The Attack on Pearl Harbor:
patrols N of Oahu during the attack on Pearl Harbor. Its mission is to
reconnoiter and attack any ships that try to sortie from Pearl Harbor.
10 December 1941:
I-6 reports sighting a LEXINGTON-class aircraft
carrier and two cruisers heading NE. Vice Admiral Shimizu, in KATORI at
Kwajalein, orders all of SubRon 1 boats, except the Special Attack Force, to
pursue and sink the carrier. I-15, I-9, I-17, I-19, I-21, I-23 and I-25 set off
at flank speed after the carrier.
14 December 1941:
After an unsuccessful pursuit of the carrier, I-15
and the other submarines, joined by I-10 and I-26, are ordered to sail to the
West Coast of the United States and attack American shipping. I-15 is assigned
to patrol west of the Farallon Islands N of San Francisco.
The Imperial General Headquarters orders the IJN to shell the U.S. West
Coast. Vice Admiral Shimizu issues a detailed order on the targets. I-15, I-9,
I-10, I-17, I-19, I-21, I-23, I-25 and I-26 are each to fire 30 shells on the
night of 25 December. Rear Admiral Sato, aboard I-9, is charged to execute the
17 December 1941:
I-15 surfaces around midnight near the Farallones to
recharge her batteries. Her crew is given a chance to see the lights of San
22 December 1941:
Admiral Yamamoto Isoroku, CINC, Combined Fleet,
postpones the Christmas Eve attack until 27 December.
27 December 1941:
Most of the I-boats off the coast have depleted
their fuel reserves. The Naval General Staff decides that the shelling of
densely populated areas, such as Los Angeles and San Francisco, will result in
civilian losses and retaliation by the Americans. Vice Admiral Shimizu cancels
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 Kawanishi H8K1 "Emily" flying boats. The plan calls for the
planes to depart Wotje in the Marshalls and fly to French Frigate Shoals in the
Hawaiian Islands where they are to be refueled by I-class submarines.
11 January 1942:
I-15 arrives at Kwajalein. That same day, LtCdr J. H.
Willingham's USS TAUTOG (SS-191) observes three IJN subs going into Kwajalein,
one of which may have been I-15.
1 February 1942:
I-15 is reassigned to SubRon 1, SubDiv 2.
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 SBD "Dauntlesses" of VB-6 and VS-6 make the first attack
followed by a second wave of TBD "Devastator" torpedo planes of VT 6.
During the first wave, I-9, I-15, I-17, I-19 and I-25 dive to the bottom
in 150 feet of water. VT-6 erroneously claims two subs sunk, but Halsey's force
does sink a transport and damage Vice Admiral Shimizu's flagship light cruiser
KATORI. I-23, submarine depot ship YASUKUNI MARU and several other important
ships are also damaged in the raid.
Two hours after the attack, Sixth Fleet HQ orders SubRon 1's I-9, I-15,
I-17, I-19, I-23, I-25, I-26, RO-61 and RO-62 to put to sea and intercept the
3 February 1942:
I-15, I-19, I-23 and I-26 are recalled to participate
in Operation K-1. The other submarines search unsuccessfully for Halsey's task
force S of Oahu.
5 February 1942: Operation "K-1" - The Second Air Attack on Pearl
Arrives at Kwajalein. Five submarines are selected to participate in
Operation K-1. I-19, I-15 and I-26's E14Y floatplanes are removed and their
hangar space is fitted with six fuel tanks each to store aviation fuel. The
objective of the attack is to bomb Pearl's "Ten Ten Dock" and disrupt ship
The I-9 is assigned to take up station midway between Wotje and the
Shoals and act as a radio beacon for two Yokohama Kokutai "Emily" flying boats.
I-19, I-15 and I-26 are to refuel the flying boats at the Shoals. I-23 is to
stand by 10 miles south of Pearl Harbor, provide weather reports and act in an
air-sea rescue capacity.
20 February 1942:
Vice Admiral Wilson Brown Jr's (later President
Roosevelt's Naval Aide) Task Force 11's USS LEXINGTON (CV-2) is en route to
attack Rabaul. The task force is spotted by a Kawanishi H6K "Mavis" flying boat
of the Yokohama Kokutai. Since surprise is lost, the American attack is
Task Force 11 is attacked off Bougainville by the 4th Kokutai's naval
land-based bombers, but the Japanese are beaten off with heavy losses.
That same day, I-15 departs Kwajalein to intercept the enemy carrier off
2 March 1942:
Diverted to French Frigate Shoal to participate in
4 March 1942:
I-15 and I-19 arrive at the Shoal. I-26 is in reserve
and I-9, with Rear Admiral Sato embarked, is at Wotje as a radio beacon. After
dark the "Emilys" arrive, refuel and take off for Pearl Harbor. On her way back
to Kwajalein, I-15 searches for the enemy task force.
5 March 1942:
Seven hours after departing French Frigate Shoals, the
flying boats bomb Honolulu through heavy cloud cover at night. They achieve
nothing and return to the Marshall Islands.
16 March 1942:
Vice Admiral, the Marquis, Komatsu Teruhisa (former CO
of CA NACHI) assumes command of the Sixth Fleet (Submarines).
21 March 1942:
I-15, I-19 and I-26 arrive at Yokosuka for an
18 April 1942: The First Bombing of Japan: At Yokosuka,
I-15, I-19, I-25 and I-26 are in drydock. A B-25 damages light carrier RYUHO
undergoing conversion from former submarine depot ship TAIGEI in a nearby
15 May 1942:
Vice Admiral (later Fleet
Admiral) William F. Halsey's Task Force 16.2's USS HORNET (CV-8), cruisers,
destroyers and an oiler accompanied by Task Force 16.1's ENTERPRISE (CV-6) and
other cruisers, destroyers and an oiler approach to within 668 nautical miles of
Japan. Led by LtCol (later General/Medal of Honor) James H. Doolittle, 16 Army
B-25 "Mitchell" twin-engine bombers of the 17th Bomb Group take off from HORNET
and strike targets in Tokyo, Yokohama, Osaka, Nagoya and Kobe.
Departs Yokosuka on her second patrol.
17 May 1942:
Arrives at Ominato.
19 May 1942:
Departs Ominato with I-9, -17 and I-19.
20 May 1942:
I-15 is reassigned to the Northern Force.
25 May 1942:
26 May 1942:
Redirected to support CarDiv 2, then returns to the area
S of Aleutians to resume her patrol.
27 May 1942: Operation "AL": The Invasion of the Western
I-9 launches her floatplane to reconnoiter Attu, Kiska and nearby
islands. I-15 and I-17 carry out periscopic observations. That day, I-15
5 June 1942:
Twenty ships of Vice Admiral Hosogaya Boshiro's (former
CO of MUTSU) Fifth Fleet, including light cruisers KISO and TAMA, three
destroyers, three corvettes, three minesweepers and four transports land Rear
Admiral (later Vice Admiral) Omori Sentaro's (former CO of ISE) Occupation Force
on Attu without opposition.
7 June 1942:
Early in the morning, I-15 reconnoiters Kiska once more
before Captain (later Rear Admiral) Ono Takeji's Occupation Force occupies the
island without opposition. On that day, I-15 is attacked by a PBY "Catalina",
but the submarine is not hit and suffers no damage.
Later, I-9, I-15, I-17 and I-19 form a patrol line W of Kiska, moving
from S to N in search of American cruisers reported earlier.
19 June 1942:
I-15 conducts a periscope observation of Dutch Harbor.
30 June 1942:
Reassigned to the Advance Force, SubRon 1 in SubDiv 2.
7 July 1942:
Returns to Yokosuka.
14 July 1942:
I-15 is SubRon 1's SubDiv 2 with I-17 and I-19.
15 August 1942:
SubDiv 2 departs Yokosuka on her third patrol to
operate E of the Solomons.
7 August 1942: American Operation "Watchtower" - The Invasion of
Guadalcanal, British Solomon Islands:
Rear Admiral (later Admiral) Richmond
K. Turner's Amphibious Task Force 62, covered by Vice Admiral (later Admiral)
Frank J. Fletcher's Task Force 61 and Rear Admiral (later Admiral) John S.
McCain's Task Force 63's land-based aircraft, lands Maj Gen (later
Gen/Commandant) Alexander A. Vandergrift's 1st Marine Division on Guadalcanal
opening a seven month campaign to take the island.
23 August 1942: Operation "KA" - The Reinforcement of
SubDiv 2 arrives in the Solomon Islands and takes up a patrol
line east of the Santa Cruz Islands to cover the landing of troops on
Guadalcanal in Operation KA.
24 August 1942: The Battle of the Eastern Solomons:
(later Admiral) Frank J. Fletcher's Task Force 61's USS SARATOGA (CV-3) and
ENTERPRISE (CV-6) launches aircraft that sink light carrier RYUJO. In turn,
CarDiv 1's SHOKAKU and ZUIKAKU launch aircraft that find and damage ENTERPRISE.
25 August 1942:
At 0145 (local), Cdr Ishikawa sights an enemy task
force. He recognizes ENTERPRISE, battleship USS NORTH CAROLINA (BB-55), two
cruisers and five destroyers. Cdr Ishikawa wants to conduct a coordinated
attack,so he tries to contact I-17 patrolling nearby with sonar "pings" using
Morse code, but I-17 fails to get the message.
Two of the screening destroyers detect I-17 and drop some depth charges.
After the attack ends, I-15 surfaces and maintains contact until 0300. Rear
Admiral Yamazaki orders I-15 and I-17 to chase the task force.
That evening, aircraft from SARATOGA damage seaplane carrier CHITOSE.
26 August 1942:
The Commander, Advance Force orders I-15, I-11, I-17,
I-19, I-26, I-33, I-174 and I-175 to deploy from the S to the E of San Cristobal
Island to interdict American supply and reinforcements for Guadalcanal.
28 August 1942:
Around midnight, Cdr Ishikawa is patrolling E of San
Cristobal. I-15 sights an American carrier heading south. Vice Admiral Komatsu
orders I-15, I-17 and I-33 to chase it, but no contacts are made.
10 September 1942:
I-15, I-9, I-17, I-19, I-21, I-24, I-26 and I-33
begin patrols between Ndeni Island and San Cristobal Island.
13 September 1942:
At 0930, an H8K "Emily" reconaissance aircraft of
the Yokohama NAG, reports a task force 345 miles SSE of Tulagi. I-9 and I-31 are
near the area, but I-15, I-17, I-21, I-24, I-26 and I-33 are also directed to
form a patrol line in the area.
15 September 1942:
Off Guadalcanal. At 1145, the nearby I-19 fires a
salvo of six torpedoes at USS WASP (CV-7). Two hit WASP and start an
uncontrollable fire. Three other torpedoes miss and continue on almost to the
limit of their range. One hits NORTH CAROLINA, another hits the destroyer
O'BRIEN (DD-415) and the last just misses USS HORNET (CV-8). WASP has to be
abandoned near 12-18S, 164-15E. 
Cdr Ishikawa confirms the sinking of WASP by I-19.
20 September 1942:
I-15, I-17, I-19, I-26, I-33, I-174 and I-175
depart the assigned area.
25 September 1942:
Arrives at Truk.
5 October 1942:
Reassigned to the 2nd Reconnaissance Unit (later
directly to SubRon 1). Departs Truk with with I-17 and I-26 to operate E of
12 October 1942:
Solomons. Arrives at the Indispensable Strait on her
fourth patrol to refuel an Aichi E13A1 "Jake" three-seat reconnaissance
floatplane of the "R" Area Air Force based at Shortland and Rekata Bay.
13 October 1942:
In the morning, the "Jake" sights a task force
including USS HORNET (CV-8) E of Malaita.
14 October 1942:
Refuels a "Jake" from CHITOSE.
16 October 1942:
Refuels a "Jake" which later sights USS HORNET. I-26
is vectored to the area.
18 October 1942:
Departs the Indispensable Strait.
19 October 1942:
Rear Admiral Yamazaki orders SubRon 1 to take up
picket positions west of Espiritu Santo.
22 October 1942:
I-15, I-17 and I-26 are assigned to patrol W of San
Cristobal and prevent enemy reinforcements from landing on Guadalcanal.
26 October 1942: The Battle of Santa Cruz:
Rear Admiral (later
Admiral) Thomas C. Kinkaid's Task Force 16 and Rear Admiral George D. Murray's
Task Force 17 engage Vice Admiral Nagumo Chuichi's carrier force.
ENTERPRISE (CV-6) is damaged by planes from the carriers JUNYO and the
SHOKAKU. JUNYO's planes damage SOUTH DAKOTA (BB-57) and SAN JUAN (CL-54). Planes
from JUNYO, SHOKAKU and ZUIKAKU damage HORNET (CV-8). USS PORTER (DD-356) is
scuttled by SHAW (DD-373). Much later, IJN destroyers scuttle the hulk of HORNET
Douglas SBD "Dauntless" dive-bombers of VS-10 from ENTERPRISE damage the
carrier ZUIHO and SBDs from HORNET damage carrier SHOKAKU and destroyer
TERUTSUKI. Grumman TBF "Avenger" torpedo-bombers from HORNET damage cruiser
27 October 1942:
200 miles W of Espiritu Santo. At 0350, Cdr Ishikawa
sights a major enemy task heading S from Santa Cruz. I-15 may have also been
sighted by the Americans. At 0414, while taking evasive action to avoid the
submarine contact, SOUTH DAKOTA and MAHAN (DD-364) collide. Damage to both ships
I-21 and I-24 also sight the American forces. They fire a salvo of
torpedoes but miss new battleship USS WASHINGTON (BB-56). I-15 proceeds to an
area SW of San Cristobal.
3 November 1942:
At 1701, I-15 sends a regular situation report, the
last message received from her.
10 November 1942:
Off Cape Recherche, San Cristobal. At 0230, I-15 is
recharging her batteries on the surface. LtCdr John Tennent's USS SOUTHARD
(DMS-10), an old four-stack destroyer (ex-DD-207) converted to a fast
minesweeper, is carrying supplies from Espiritu Santo to Guadalcanal.
SOUTHARD's lookouts spot a surfaced submarine.
SOUTHARD closes on I-15. At 0231, Tennent opens fire with his 4.5-in main
battery. Cdr Ishikawa crash-dives. I-15 quickly moves to the attack. Ishikawa
reportedly fires two torpedoes at the minesweeper, but they both miss. At 0242,
SOUTHARD acquires I-15 on sonar and commences the first of six depth-charge
attacks she delivers over the next several hours. The soundmen of I-17l,
patrolling nearby, report numerous DC explosions from that direction.
At 1003, damage to I-15 forces Ishikawa to surface at the south end of
Indispensible Strait. SOUTHARD opens fire from about 2,000 yards. A salvo hits
the I-15's conning tower. She sinks by the bow with all 91 hands at 10-13S,
5 December 1942:
Presumed lost in the Guadalcanal area.
24 December 1942:
Removed from the Navy List.
 Several accounts erroneously credit I-15 with hitting
NORTH CAROLINA, but all the torpedoes were actually fired by I-19.
SOUTHARD is often credited with the sinking of I-172, lost in roughly the same
area a week earlier.
Thanks go to Dr. Higuchi Tatsuhiro of Japan.
– Bob Hackett and Sander Kingsepp.
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