SENSUIKAN!

© 2001-2017 Bob Hackett & Sander Kingsepp
Revision 4

18 June 1931:
Laid down at Kure Navy Yard.

26 June 1933:
Launched as I-68.

15 November 1933:
Cdr (later Rear Admiral) Tsuruoka Nobumichi (43)(former CO of I-66) is appointed the Chief Equipping Officer (CEO).

31 July 1934:
I-68 is completed, commissioned in the IJN and attached to Kure Naval District. Assigned to SubDiv 12. Cdr Tsuruoka Nobumichi is the CO.

15 November 1934:
LtCdr (Rear Admiral, posthumously) Ota Nobunosuke (47)(former CO of FUYO) is appointed the CO.

15 November 1935:
LtCdr (Rear Admiral, posthumously) Kayabara Yasuchika (49)(former CO of I-124) is appointed the CO.

1 December 1937:
Lt (later Captain) Hatanaka Sumihiko (49)(former torpedo officer of MIKUMA) is appointed the CO.

15 December 1938:
Cdr (later Captain) Uchino Shinji (49)(former CO of I-5) is appointed the CO.

1 September 1939:
LtCdr (Captain, posthumously) Muraoka Tomiichi (52) (former CO of I-65) is appointed the CO.

19 October 1940:
Placed in reserve at Kure.

25 July 1941:
LtCdr (later Captain) Nakamura Otoji (52)(former CO of RO-60) is appointed the CO.

11 November 1941: Operation Z:
I-68 is in Vice Admiral Shimizu Mitsumi's (former CO of ISE) Advance Expeditionary Force (Sixth Fleet) with Rear Admiral (later Vice Admiral) Miwa Shigeyoshi's (former CO of KINU) SubRon 3 in Captain (later Rear Admiral) Nakaoka Nobuki's SubDiv 12 with I-69 and I-70.

Admiral Shimizu convenes a meeting of all his commanders aboard his flagship, light cruiser KATORI. The commanders are briefed on the planned attack on Pearl Harbor. I-68 departs Saeki for Kwajalein.

23 November 1941:
Departs Kwajalein for Hawaii 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: The attack on Pearl Harbor:
SubRon 3 is deployed S of Oahu. Its mission is to reconnoiter and attack any ships that try to sortie from Pearl Harbor. I-68 is assigned to patrol from 25 to 50 miles SW of Oahu with I-69, I-70, I-72 and I-73.

8 December 1941:
I-68 and I-69 are ordered to lay off the entrance to Pearl Harbor to rescue midget submarine crews (none return). Returns to her former station thereafter.

13 December 1941:
SW of Oahu. I-68 is subjected to 21 separate depth-charge attacks on this and later days. The last attack wrecks many of her battery cells and causes flooding in her aft torpedo room.

17 December 1941:
LtCdr Nakamura decides to terminate his patrol and heads for Kwajalein.

28 December 1941:
Returns to Kwajalein.

31 December 1941:
Departs Kwajalein for Kure.

9 January 1942:
Arrives at Kure for repairs.

17 January 1942:
Hashirajima. LtCdr Nakamura pays a call on the battleship YAMATO. He briefs the CINC, Combined Fleet, Admiral (Fleet Admiral, posthumously) Yamamoto Isoroku (former CO of AKAGI), and his staff on I-68's depth-chargings during the Hawaii operation.

31 January 1942:
LtCdr (later Cdr) Tanabe Yahachi (56)(former CO of RO-59) is appointed the CO.

26 April 1942:
ComSubRon 3 Rear Admiral Miwa is relieved by Rear Admiral (later Vice Admiral) Kono Chimaki (former CO of FUSO).

20 May 1942:
I-68 is renumbered I-168.

23 May 1942:
Departs Kure on her second war patrol to reconnoiter Kure Atoll and the Midway Island prior to its capture.

31 May 1942:
Reconnoiters Kure Atoll.

2 June 1942:
At dawn, LtCdr Tanabe arrives NW of Midway and conducts the first periscope reconnaissance of Sand Island. Tanabe reports "unusually frequent patrol aircraft launches".

3-4 June 1944:
I-168 circumnavigates Midway, providing weather data to Headquarters, Combined Fleet.

4 June 1942: Operation "MI":
Early in the morning, LtCdr Tanabe, his navigator and the gunnery officer witness the air attack on Midway through the periscope. At 1025, American dive-bombers reduce carriers AKAGI, KAGA and SORYU to burning wrecks, but HIRYU is not damaged. At 1054, she launches 18 D3A1 "Val" dive-bombers and six A6M2 "Zeke" fighters that follow the American planes and find their carriers.

HIRYU's dive-bombers attack USS YORKTOWN (CV-5). A bomb hits the flight deck aft of the island and sets afire three planes in the hangar below. A second delayed action bomb penetrates three decks and explodes in the uptakes of the stack, snuffing out the boilers. YORKTOWN's speed falls to six knots. A third bomb hits her forward elevator. Damage control crews fight the fires, but at 1220 she is brought to a full stop for repairs. She has to work up steam to get underway again.

Six Japanese planes survive and radio that the American carrier is burning and that two more carriers are present. At 1245, HIRYU launches a second strike of 10 "Kate" torpedo planes and six fighters. Under orders from ComCarDiv 2, Rear Admiral (Vice Admiral, posthumously) Yamaguchi Tamon to engage only an undamaged carrier, the Kates attack what appears to be one; but it is, in fact, YORKTOWN whose fires have been put out and steam restored.

By 1440, the Kates launch Type 91 torpedoes from both sides of YORKTOWN's bow. YORKTOWN, making 19 knots, dodges two torpedoes, but two others hit her port side, cut all electrical power and jam her rudder 15 degrees to port. She comes to a stop and takes on a list that increases to 26 degrees. At 1455, YORKTOWN heels over and her flight deck almost touches the sea. Captain Elliott Buckmaster orders his 3,000 men to abandon ship. Destroyers pick up the survivors.

From his flagship battleship YAMATO, Admiral Yamamoto issues orders for a submarine bombardment of the airfield on Eastern Island, Midway until 0100 when I-168 is to be relieved by CruDiv 7's MOGAMI, MIKUMA, KUMANO and SUZUYA. Later the cruisers' orders are canceled. Additionally, ComSubRon 3 orders Tanabe to remain in vicinity of Midway in order to report about the subsequent aircraft traffic.

Around 2154 I-168 surfaces 4,500 yds E of the eastern tip of Eastern Island and proceeds to Sand Island surfaced.

5 June 1942:
At 0124, I-168 surfaces within 1,100 yds SW of Midway and opens fire with her 10-cm deck gun. I-168 fires six shells but inflicts no damage. The Marine shore batteries snap on searchlights and their return fire forces I-168 to submerge. The submarine is briefly chased and depth-charged by a patrol vessel.

At 0652, cruiser CHIKUMA's No. 2 floatplane discovers the damaged YORKTOWN. The plane's signal vectors I-168 to the carrier. CHIKUMA's No. 4 Aichi E13A1 "Jake" scout of Vice Admiral (Admiral, posthumously) Nagumo Chuichi's Kido Butai, radioes that it has sighted an enemy carrier 150 miles NNE of Midway. At 1055 LtCdr Tanabe receives an order from ComSubRon 3 to pursue and sink the carrier.

While running on the surface towards the carrier's reported position, I-168 is attacked by a PBY "Catalina" patrol plane. Tanabe dives and escapes undamaged.

6 June 1942:
At 0410, one of I-168's lookouts spots YORKTOWN about 12 miles away. At 0600, Tanabe spots the first destroyers. He submerges and slows to three knots. As he closes, he sees six destroyers circling a mile away. The minesweeper VIREO has YORKTOWN in tow. At 0605, USS HAMMANN (DD-412) puts a salvage party aboard the carrier. HAMMANN is secured to YORKTOWN's starboard side and provides power for the carrier's pumps and foam to fight the fires.

I-168 arrives and sights the carrier and her screen. For seven hours, Tanabe skillfully makes his approach, steering by chart and sound with only a few periscope sightings. Undetected, he penetrates the destroyer and cruiser screen. At 1331, from 1,900 yards, he fires two torpedoes at the overlapping formation, followed by two more three seconds later. The first torpedo hits HAMMANN, breaks her back and sinks her in about four minutes. As she goes down, her depth charges explode and kill 81 of her 241-strong crew. At 1332, the next two torpedoes strike YORKTOWN starboard below the bridge. The fourth torpedo misses and passes astern.

At 1336, American destroyers commence a counterattack. A destroyer passes directly overhead and drops two depth charges. After more attacks the forward torpedo room and maneuvering room flood. After battery cells are extensively damaged and all crew dons gas masks. The outer and inner doors of torpedo tube No. 1 spring and admit water. The lights go out and the emergency lights come on.

At 1640, with his batteries nearly exhausted, Tanabe battle surfaces determined to go down fighting, but three destroyers USS GWIN (DD-433), HUGHES (DD-410) and MONAGHAN (DD-354) are about five miles away. Tanabe sets off at the best speed I-168 can now make - only 14 knots. Tanabe signals to the flagship of the Combined Fleet YAMATO that he has attacked and sunk the YORKTOWN. One destroyer closes within 5,470 yards, firing intermittently. After the emergency repair of an electric engine is completed, Tanabe submerges again. I-168 stays down until 2000 and then resurfaces. During 13 hours of chase, she has been attacked with some 40 depth-charges.

Contrary to Tanabe's report, YORKTOWN has not yet sunk. The two torpedo hits corrected her list from 26 to 17 degrees. Captain Buckmaster removes the salvage party and plans to resume work in the morning.

Admiral Yamamoto suspends the invasion of Midway.

7 June 1942:
At 0458, the 19,875-ton YORKTOWN rolls over to port and sinks in about 3,000 fathoms of water. LtCdr Tanabe has made the biggest kill yet by any submarine in the Pacific. [1]

19 June 1942:
Arrives at Yokosuka with nearly dry tanks. Refuels and proceeds to Kure. A big crowd greets Tanabe on I-168's arrival at Kure. Music plays and speeches are made.

26 June 1942:
I-168 is transferred to Sasebo.

30 June 1942:
Cdr (later Captain) Tonozuka Kinzo (50), the CEO of I-34, currently under construction at Sasebo, is appointed the CO of I-168 "on paper" while she undergoes battle-damage repairs.

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. Vandegrift's 1st Marine Division on Guadalcanal opening a seven-month campaign to take the island.

31 August 1942:
Repairs to I-168 are completed. LtCdr (Captain, posthumously) Watanabe Katsuji (55)(current CO of I-169) is appointed the CO of I-168 as additional duty. Departs Sasebo.

15 October 1942:
LtCdr (Cdr, posthumously) Nakajima Sakae (56)(former CO of I-157) is appointed the CO.

16 November 1942:
Truk. Vice Admiral Komatsu convenes a meeting of his submarine captains. He announces that the submarine force has been ordered by Admiral Yamamoto to organize a supply system for the IJA's 17th Army garrison on Guadalcanal.

18 November 1942:
Returns to Kure. Drydocked for repairs.

15 December 1942:
Departs Kure for Truk.

22 December 1942:
Arrives at Truk. Participates in supply missions to Guadalcanal while directly attached to the Sixth Fleet HQ.

1 January 1943:
Arrives at Guadalcanal with 15 tons of cargo but is chased away by two patrol boats after 60 per cent of the cargo is unloaded.

3 January 1943:
Arrives at Shortland, departs the next day for Truk.

7 January 1943:
Arrives at Truk, departs the next day for Kure.

14 January 1943:
Arrives at Kure.

1 February 1943:
Assigned to Northern District Force.

22 February 1943:
Departs Kure for Yokosuka.

25 February 1943:
Arrives at Yokosuka.

5 March 1943:
Departs Yokosuka for Paramushiro.

10 March 1943:
Arrives at Paramushiro.

13 March 1943:
Departs Paramushiro on her first supply run to Attu and Kiska, carrying ammuniton.

15 March 1943:
Arrives at Holtz Bay, Attu, unloads a part of her cargo, then departs for Kiska.

At 1727 (Y), the surfaced I-168 is attacked by USS S-32, patrolling off the entrance to Holtz Bay. LtCdr Maximilian G. Schmidt (USNA '32) fires a three-torpedo spread at 52-54N, 173-13E; all miss. A muffled explosion is heard and S-32's soundman reports that enemy's propeller noises have stopped, but the CO of S-32 observes the "I-1 class submarine" until 1736 when the visual contact is lost. [2]

17 March 1943:
Arrives at Kiska, unloads her ammunition cargo and 6 tons of provisions, then departs to patrol in an area S of Amchitka.

1 April 1943:
Returns to Kiska in company of I-169. Takes aboard sick personnel of the Kiska garrison and the ground personnel of the 452nd Naval Air Group.

4 April 1943:
Returns to Paramushiro.

10 April 1943:
Departs Paramushiro on her second supply run to Attu and Kiska, carrying ammunition and mail.

12 April 1943:
Arrives at Attu, unloads a part of her cargo, then departs for Kiska.

14 April 1943:
Arrives at Attu, embarks several staff officers.

16 April 1943:
Departs Attu for Kiska.

19 April 1943:
Arrives at Kiska, unloads her cargo.

9 May 1943:
Returns to Yokosuka. Reassigned to SubRon 3.

12 July 1943:
Departs Kure, still under LtCdr Nakajima.

22 July 1943:
Arrives at Truk.

25 July 1943:
Departs Truk for Rabaul.

27 July 1943:
I-168 sends a regular situation report while negotiating the Isabel Strait. This is the last message from I-168.

At dusk around 1754, I-168 sights a surfaced enemy submarine in the Steffen Strait between New Ireland and New Hanover. LtCdr Nakajima fires a torpedo at the submarine, but misses. Lookouts on LtCdr Walter E. Ebert's USS SCAMP (SS-277) spot the incoming torpedo. Ebert goes ahead full and crash dives. He levels off at 220 ft, lets the torpedo pass overhead and returns to periscope depth. At 1812, Ebert fires four torpedoes at I-168 that sink her 60 miles off New Hanover at 02-50S, 149-01E.

10 September 1943:
Presumed lost with all 97 hands in the area N of Rabaul.

15 September 1943:
SubRon 3 is disbanded.

15 October 1943:
Removed from the Navy List.

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Authors' notes:
[1] On 19 May 1998, Dr. Robert D. Ballard, with a National Geographic Society-sponsored Midway deep-sea expedition, finds YORKTOWN sitting upright, virtually intact, in 16,650 feet of water. See http://www.nationalgeographic.com/midway

[2] S-32's target has been erroneously identified as RO-103, operating off Rabaul at that time.

Thanks go to Dr Higuchi Tatsuhiro of Japan, Jean-Francois Masson of Canada and Andrew Obluski of Poland.

- Bob Hackett and Sander Kingsepp.

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