SENSUIKAN!

© 2001-2017 Bob Hackett & Sander Kingsepp

15 February 1933:
Laid down at Kawasaki's Kobe Yard.

25 August 1934:
Launched and numbered I-71.

15 February 1935:
LtCdr (promoted Cdr 15 December) Minakuchi Hyoe (46)(former division officer of ONDO) is appointed the Chief Equipping Officer (CEO). [1]

24 December 1935:
I-71 is completed, commissioned in the IJN and attached to Kure Naval District. Cdr (later Capt) Minakuchi Hyoe is the CO.

30 June 1936:
LtCdr (later Cdr) Nagai Komei (48)(former CO of I-1) is appointed the CO.

31 July 1937:
LtCdr (later Captain) Koizumi Kiichi (49)(former CO of I-124) is appointed the CO.

19 March 1938:
LtCdr (Rear Admiral, posthumously) Narahara Seigo (48) (former CO of I-54) is appointed the CO. [2]

30 July 1938:
LtCdr (later Captain) Hori Takeo (50)(former damage control officer of NARUTO) is appointed the CO.

10 October-20 November 1939:
LtCdr Hori is appointed the CO of I-72 as an additional duty.

31 July 1941:
LtCdr (later Cdr) Kawasaki Rokuro (51)(former CO of I-52) is appointed the CO. [3]

11 November 1941:
I-71 is in SubRon 3's SubDiv 20 in the Sixth Fleet. LtCdr Kawasaki Rokuro is the Commanding Officer. Departs Saeki with I-68, I-69, I-70, I-72 and I-73.

20 November 1941:
Arrives at Kwajalein.

23 November 1941:
Departs Kwajalein.

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). [4]

5 December 1941:
I-71 reconnoiters off the Hawaiian Islands in the Alalakeiki Channel between Maui and Kahoolawe. Later, I-71 and I-73 reconnoiter the Lahaina anchorage.

7 December 1941: The Attack on Pearl Harbor:
SubRon 3 is deployed south of Oahu. Its mission is to reconnoiter and attack any ships that try to sortie from Pearl Harbor. I-71 is assigned to patrol from 25 to 50 miles southeast of Oahu with I-72 and I-73. During this mission in December, I-71 is subjected to several depth-charge attacks.

21 December 1941:
After dark, I-71 surfaces off Johnston Island and attempts to shell it, but fire is returned and she dives again.

28 December 1941:
Returns to Kwajalein with I-68 and I-72.

12 January 1942:
Departs Kwajalein, on her second war patrol, with I-72 and I-73 to relieve I-18, I-22 and I-24 that form a picket line in the Hawaii area.

28 January 1942:
30 miles N of Upolu Point, Alenuihaha Channel, Hawaii. At dawn, I-71 attacks a three-ship convoy bound from Kahului, Maui for Hilo, Hawaii that includes the 622-ton Army transport GENERAL ROYAL T. FRANK carrying 26 Army recruits and small freighter KALAE with a barge in tow. Both ships are being escorted by the old flush-deck destroyer USS TREVER (DD-339). I-71 attacks the convoy, initially missing GENERAL ROYAL T. FRANK with two torpedoes. Around 0710 she is hit by a third torpedo, explodes and sinks in less than 30 seconds off the Maui's Hana coast. Of 60 people aboard, 36 are rescued by KALAE.

1 February 1942:
Vice Admiral (later Fleet Admiral) William F. Halsey Jr's (former CO of SARATOGA, CV-3) Task Force 8's USS ENTERPRISE (CV-6) raids Kwajalein and Wotje in the Marshall Islands. Douglas SBD "Dauntless" dive-bombers 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). Shimizu is wounded. I-23, submarine depot ship YASUKUNI MARU and several other important ships are also damaged in the raid.

16 February 1942:
I-71 arrives at Kwajalein.

18 February 1942:
Departs Kwajalein with I-72.

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, but is spotted by a Kawanishi H6K "Mavis" flying boat of the Yokohama Kokutai. Since surprise is lost, the American attack is cancelled. TF 11 is attacked off Bougainville by naval land-based bombers of the 4th Kokutai, but they are beaten off with heavy losses.

I-71 and I-72 are diverted E of Wake Island.

6 March 1942:
I-71 arrives at Kure.

15 April 1942:
Departs Kure to form a picket line.

16 March 1942:
Vice Admiral, the Marquis, Komatsu Teruhisa (former CO of CA NACHI) assumes command of the Sixth Fleet (Submarines). Vice Admiral Shimizu, wounded in the raid on Kwajalein, returns to Japan to convalesce.

20 March 1942:
SubDiv 20 is disbanded. I-71 is reassigned to SubDiv 12.

15 April 1942:
Departs Kure on her third war patrol with I-72 to form a picket line.

10 May 1942:
Arrives at Kwajalein.

20 May 1942:
I-71 is renumbered as I-171.

24 May 1942: Operation "K-2" - The second surprise raid on Pearl Harbor:
Prior to the Battle of Midway, I-171 departs Kwajalein to act as the radio beacon for Kawanishi H8K "Emily" flying boats east of the French Fregate Shoal.

May-June 1942: Operation "MI" - The Battle of Midway:
I-171 is in Rear Admiral Kono Chimaki's SubRon 3 with I-168, I-169, I-174 and I-175. She is part of a picket line formed in the Hawaii area. SubRon 3 is deployed between 20N, 166-20W and 23-30N, 166-20W.

20 June 1942:
Returns to Kwajalein with I-174 and I-175.

5 July 1942:
LtCdr (Cdr, posthumously) Kobayashi Shigeo (56)(former CO of I-154) is appointed the CO.

8 July 1942:
Departs Kwajalein on her fourth war patrol to reconnoiter the Fiji-Samoa area.

16-24 July 1942:
Fiji. LtCdr Kobayashi reports that there are no ships in Suva harbor, then heads for the Samoa area.

28 July 1942:
I-171 reconnoiters Pago-Pago.

29 July 1942:
Off Tutuila, LtCdr Kobayashi sights and attacks an unidentified merchant, but misses with a torpedo.

12 August 1942:
Arrives at Truk.

17 August 1942:
Departs Truk.

24 August 1942:
Arrives at Kure for an overhaul.

10 October 1942:
LtCdr Kobayashi is appointed the Chief Equipping Officer of RO-106 (until 10 November) and RO-107 (until 10 December) as an additional duty.

15 February 1943:
Departs Kure on a supply run to Kiska.

26 February 1943:
Arrives at Kiska.

2 March 1943:
Departs Kiska.

18 March 1943:
Arrives at Paramushiro, Kuriles.

20 March 1943:
Oiler TEIYO MARU refuels I-171, I-169 and I-31.

22 March 1943:
Departs Paramushiro on her fifth war patrol to form a picket line.

25 March 1943:
Takes up scouting line duties at 52-55N, 174 E.

6 April 1943:
Arrives at Yokosuka.

11 May 1943: American Operation "Landcrab" - The Invasion of Attu, Aleutians:
Rear Admiral (later Admiral) Thomas C. Kinkaid's Task Force 16, covered by Rear Admiral Francis W. Rockwell's Task Force 51, lands elements of the Army's 4th and 7th Infantry Divisions under the command of Maj Gen Eugene M. Landrum at Holtz Bay and Massacre Bay that later capture the island.

13 May 1943:
SubDiv 12 is reassigned to Northern Force.

21 May 1943: Operation "KE" - The Evacuation of Kiska:
The Imperial General Headquarters decides to evacuate the garrison at Kiska Island, Aleutians. That day, I-171 departs Yokosuka for Kiska on her sixth war patrol. En route, she is attacked by a patrol craft.

16 June 1943:
Arrives at Paramushiro. Oiler TEIYO MARU refuels I-171.

21 June 1943:
Vice Admiral (Admiral, posthumously) Takagi Takeo (former CO of MUTSU) assumes command of the Sixth Fleet (Submarines). Vice Admiral Komatsu is later appointed President of the Etajima Naval Academy.

26 June 1943:
Departs Paramushiro, on her seventh war patrol, with I-175 to raid enemy communications S of Amchitka, Aleutians.

3 August 1943:
Returns to Paramushiro.

5 August 1943:
Departs Paramushiro.

10 August 1943:
Arrives at Kure. SubDiv 12 is reassigned to SubRon 3.

30 August 1943:
LtCdr (Cdr, posthumously) Shimada Takeo (59)(former CO of I-121) is appointed the CO.

17 September 1943:
Departs Kure.

25 September 1943:
Arrives at Truk.

7 October 1943:
Departs Truk on her eighth war patrol, with Capt Kobayashi Hajime (48), ComSubDiv 12 embarked, to reconnoiter the area east of the New Hebrides.

19 October 1943
Vice Admiral Takagi orders ComSubDiv 12 aboard I-171 to assume temporary command over I-21 and I-32 to intercept six American fleet oilers that were sighted by I-36 off Hawaii. A Kawanishi H8K "Emily" flying boat of the 802nd NAG based at Jaluit fails to locate the oilers.

15 November 1943:
Returns to Truk.

7 December 1943:
Truk. HEIAN MARU transfers ammunition to I-171.

17 December 1943:
Truk. HEIAN MARU transfers torpedoes to I-171.

22 December 1943:
Truk. HEIAN MARU transfers torpedoes to I-171 and stores to RO-42.

25 December 1943:
Truk. HEIAN MARU transfers torpedoes to I-171.

29 December 1943:
Truk. HEIAN MARU transfers stores to I-171.

7 January 1944:
Truk. HEIAN MARU embarks torpedoes from I-171.

9 January 1944:
Departs Truk.

13 January 1944:
Arrives at Rabaul.

17 January 1944:
Departs Rabaul for Gali, New Guinea.

22 January 1944:
Arrives at Gali, embarks some passengers and departs for Rabaul.

26 January 1944:
Arrives at Rabaul.

30 January 1944:
Departs Rabaul on a supply run to Buka, carrying rubber containers on her deck. I-171 is the second submarine after I-181 to supply Buka's garrison.

31 January 1944:
15 miles W of Buka Island. LtCdr Earle K. McLaren's USS GUEST (DD-472) and LtCdr Richard R. Pratt's HUDSON (DD-475) are covering the transports that land Marine raiders on Green Island.

1 February 1944:
GUEST and HUDSON pick up a surface contact on their SG radars at 3,500 yards. The submarine - probably I-171 - dives, but the destroyers reacquire her on sonar. Both destroyers make depth-charge runs that sink I-171 at 05-37S, 154-14E. [5]

5 February 1944:
At 1652, USN codebreakers intercept and decrypt a message that reads: "I-171 departed Rabaul January 30th to engage in transportation operations to Buka but she had not arrived at Buka by February 5th at 1800 as scheduled. After 3rd, she was called a number of times but there is no response. We have no further information on her ----- personnel items------."

12 March 1944:
I-171 is presumed lost with all 91 hands off Buka.

14 March 1944:
At 0754, USN codebreakers intercept and decrypt a message from the Commander Southeastern Area Submarine Force that reads: "I-171 departed Rabaul January 30, arrived Buka Feb. 2 [blurred number might be 1 or might be 2]. Completed unloading men and cargo and (continued on special transportation duties). Has not been heard from since February 1. According to report of naval force at Buka, an enemy destroyer was (sighted) to west of Buka that date. It is assumed that Captain and all hands died in battle. -----."

30 April 1944:
Removed from the Navy List.

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Authors' Notes: [1] Boyd and Yoshida (1996) identify that officer as Minokuchi Hyoe; however, the IJN Naval Register of 1936 renders his family name as Minakuchi. The year of his graduation given in the 1996 source is likewise incorrect.

[2] While several Western sources render Narahara Seigo's first name as Shogo, the prewar IJN Naval Registers (1926 et alia) unanimously identify that same officer as Narahara Seigo.

[3] Boyd and Yoshida (1996) identify that officer as Kawasaki Mutsuro; however, the IJN Naval Register of 1937 renders his first name as Rokuro.

[4] Mt. Niitaka, located in Formosa (now Taiwan), was then the highest point in the Japanese Empire.

[5] On 1 February 1944 LtCdr Takeuchi Yoshitake (59)(former CO of I-158) was appointed to become the next skipper of I-171 after its return. He remained in that capacity until 12 February.

Thanks go to Dr. Higuchi Tatsuhiro of Japan. Thanks also go to John Whitman of the USA for info on CNO intercepts of Japanese messages.

– Bob Hackett and Sander Kingsepp.

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