(Type B1 submarine - colorized photo by Irootoko Jr)

IJN Submarine I-15: Tabular Record of Movement

2001-2016 Bob Hackett & Sander Kingsepp
Revision 4

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 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 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:
I-15 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 order.

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 Francisco.

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 the shelling.

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 enemy carriers.

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 Harbor:
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 repair activities.

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 cancelled.

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 Rabaul.

2 March 1942:
Diverted to French Frigate Shoal to participate in Operation "K-1".

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 overhaul.

18 April 1942: The First Bombing of Japan:
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.

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 drydock.

15 May 1942:
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:
Reconnoiters Adak.

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 Aleutians:
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 reconnoiters Kodiak.

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 periscopic 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 Guadalcanal.
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:
Vice Admiral (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. [1]

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 Guadalcanal.

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:
Rear Admiral Mito Hisashi assumes command of SubRon 1 from Rear Admiral Yamazaki. 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 with torpedoes.

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 CHIKUMA.

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 is severe.

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:
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 to Guadalcanal. SOUTHARD's lookouts spot the 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 fires two torpedoes at the minesweeper, but they both miss. At 0242, SOUTHARD acquires I-15 on sonar and drops the first of six depth-charge salvos she delivers over the next several hours. I-17l, patrolling nearby, observes the DC explosions.

At 1003, damage to I-15 forces Ishikawa to surface at the south end of Indispensible Strait. SOUTHARD opens fire from about a mile away. A salvo hits the I-15's conning tower. She sinks by the bow with all 91 hands at 10-13S, 161-09E. [2]

5 December 1942:
Presumed lost in the Guadalcanal area.

24 December 1942:
Removed from the Navy List.

Authors' Notes:
[1] Several accounts erroneously credit I-15 with hitting NORTH CAROLINA, but all the torpedoes were actually fired by I-19.
[2] USS 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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