View source for Japanese submarine I-8

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{{Infobox ship image
|Ship image=File:I-8.jpg
|Ship caption=''I-8'' entering [[Kagoshima Bay]] on the coast of [[Japan]] on 12&nbsp;September&nbsp;1939.
}}
{{Infobox ship career
|Hide header=
|Ship country=[[Empire of Japan]]
|Ship flag={{shipboxflag|Empire of Japan|naval}}
|Ship name=''I-8''
|Ship namesake=
|Ship ordered=
|Ship builder=[[Kawasaki Shipbuilding Corporation|Kawasaki]], [[Kobe]],&nbsp;[[Japan]]
|Ship laid down=11 October 1934
|Ship launched=20 July 1936
|Ship completed=5 December 1938
|Ship acquired=
|Ship commissioned=
|Ship decommissioned=
|Ship in service=
|Ship out of service=
|Ship struck=
|Ship homeport=
|Ship honours=
|Ship fate= Sunk 31 March 1945
|Ship status=
|Ship notes=
}}
{{Infobox ship characteristics
|Hide header=
|Header caption=
|Ship class = [[Junsen type submarine|''Junsen'']]-class J3 Type [[submarine]]
|Ship displacement=
*{{convert|2525|LT|t|0|abbr=on}} surfaced
*{{convert|3583|LT|t|0|abbr=on}} submerged
|Ship length={{convert|358.5|ft|6|in|m|abbr=on}}
|Ship beam={{convert|29|ft|8|in|m|abbr=on}}
|Ship draft={{convert|17|ft|3|in|m|abbr=on}}
|Ship propulsion=
* [[Diesel-electric]]
* 2 diesel engines, {{convert|11200|hp|kW|abbr=on}} (surfaced)
* Electric motors, {{convert|2800|hp|kW|abbr=on}} (submerged)
|Ship speed=
* {{convert|23|kn|lk=in}}  (surfaced)
* {{convert|8|kn}} (submerged)
|Ship range=  {{convert|14000|nmi|km|lk=in|abbr=on}} at {{convert|16|kn}}
|Ship test depth={{convert|100|m|ft|abbr=on}}
|Ship complement=100 officers and men
|Ship crew=
|Ship time to activate=
|Ship sensors=
|Ship EW=
|Ship armament=
* 1 × twin [[14 cm/40 11th Year Type naval gun]]<ref name="campbell">Campbell, John ''Naval Weapons of World War Two'' {{ISBN|0-87021-459-4}} p.191</ref>
* 2 × [[Type 96 25&nbsp;mm AT/AA Gun|Type 96 {{convert|25|mm|in|abbr=on}}]] AA guns
* 6 × {{convert|533|mm|in|abbr=on}} forward [[torpedo tube]]s
* 21 [[torpedo]]es
* ''[[Kaiten]]'' fittings (added&nbsp;1944–1945)
|Ship aircraft=1 × [[Yokosuka E14Y]] seaplane (removed&nbsp;1944)
|Ship aircraft facilities=*1 x [[aircraft catapult]] (removed&nbsp;1944)
*1 x [[hangar]] (removed&nbsp;1944) 
|Ship notes=
}}
|}

'''''I-8''''' was an [[Imperial Japanese Navy]] [[Junsen type submarine|Junsen III]] (or J3)-type [[submarine]] commissioned in 1938 that served during [[World War II]]. Designed as [[submarine aircraft carrier]]s, ''I-8'' and her [[sister ship]] {{ship|Japanese submarine|I-7||2}} were the largest Japanese submarines to be completed before the outbreak of the [[Pacific War|war in the Pacific]] in 1941. With embarked [[floatplane]]s, ''I-8'' participated in operations related to the [[attack on Pearl Harbor]], patrolled off the [[United States West Coast]], and took part in the [[Guadalcanal campaign]] and the [[Okinawa campaign]].

In 1943, ''I-8'' completed a technology exchange mission with a voyage to German-[[occupied France]] and back to [[Japan]], the only submarine to complete a round-trip voyage between Japan and [[Europe]] duirng World War II. Under a new [[commanding officer]] in 1944, her crew committed [[war crime]]s during anti-shipping operations in the [[Indian Ocean]]. She was sunk in 1945.
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==Construction and commissioning==

Built by [[Kawasaki Shipbuilding Corporation|Kawasaki]] at [[Kobe]], [[Japan]], with a design based on that of the [[Kaidai-type submarine|''Kaidai'' (KD)-type]] submarines,''I-8'' was [[Keel-laying|laid down]] on 11 October 1934.<ref name=ijnsubsiteI8>[http://www.ijnsubsite.info/I-Sub%20Details/I-8.htm I-8 ijnsubsite.com 19 December 2012 Accessed 30 January 2022]</ref><ref name=combinedfleetI8>{{cite web |url= http://www.combinedfleet.com/I-8.htm |title=IJN Submarine I-8: Tabular Record of Movement |first1=Bob |last1=Hackett |first2=Sander |last2=Kingsepp |work=combinedfleet.com |date=July 1, 2016|access-date=20 December 2021}}</ref> She was [[Ceremonial ship launching|launched]] on 20 July 1936<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/> and was completed and [[Ship commissioning|commissioned]] on 5 December 1938.<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/>

==Service history==

===Pre-World War II===

On the day of her commissioning, ''I-8'' was attached to the [[Yokosuka Naval District]].<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/> On 15 December 1938, she became the [[flagship]] of Submarine [[Squadron (naval)|Squadron]] 2 in the [[2nd Fleet (Imperial Japanese Navy)|2nd Fleet]], a component of the [[Combined Fleet]].<ref name=ijnsubsiteI8/> She became the flagship of Submarine Squadron 3 in the 2nd Fleet on 15 November 1939.<ref name=ijnsubsiteI8/> On 11 October 1940, she was one of 98 Imperial Japanese Navy ships that gathered along with more than 500 aircraft on the Japanese coast at [[Yokohama Bay]] for an [[Fleet Review (Japan)|Imperial fleet review]] — the largest [[fleet review]] in Japanese history — in honor of the 2,600th anniversary of the enthronement of the [[Emperor Jimmu]], Japan's legendary first [[Emperor of Japan|emperor]].<ref name=ijnsubsiteI8/><ref>{{cite web |url= http://www.combinedfleet.com/chitosesp_t.htm |title=IJN Seaplane Carrier CHITOSE: Tabular Record of Movement |first1=Athony |last1=Tully |work=combinedfleet.com |date=19 May 2014|access-date=11 December 2021}}</ref><ref>{{cite news |title=2012 Fleet Review |url=https://www.mod.go.jp/e/jdf/pdf/jdf_no35.pdf |accessdate=October 8, 2019 |work=Japan Defense Focus |date=December 2012}}</ref>

On 15 November 1940, Submarine Squadron 3 was reassigned to the [[6th Fleet (Imperial Japanese Navy)|6th Fleet]] in the Combined Fleet.<ref name=ijnsubsiteI8/> At some point, the [[submarine tender]] {{ship|Japanese submarine tender|Taigei||2}} relived ''I-8'' as squadron flagship, because on 1 October 1941, [[Rear admiral|Rear Admiral]] [[Shigeyoshi Miwa]], the commander of Submarine Squadron 3, transferred his flag from ''Taigei'' to ''I-8'', making her the squadron flagship again.<ref name=combinedfleetI8/> She subsequently conducted combat training along with the other submarines of the squadron off [[Kyushu]].<ref name=combinedfleetI8/>

By 10 November 1941, ''I-8'' had been assigned to the 6th Fleet's Advance Expeditionary Force.<ref name=combinedfleetI8/> That day, the 6th Fleet's commander, [[Vice Admiral]] [[Mitsumi Shimizu]], held a meeting with the [[commanding officer]]s of the submarines of Submarine Squadron 3 aboard his flagship, the [[light cruiser]] {{ship|Japanese cruiser|Katori||2}}, which was [[anchor]]ed in [[Saeki Bay]] on the coast of Kyushu , and his chief of staff briefed them on plans for Operation Z, the upcoming surprise [[attack on Pearl Harbor]] in [[Hawaii]].<ref name=combinedfleetI8/> The attack would begin the [[Pacific War|Pacific campaign]] and bring Japan and the [[United States]] into [[World War II]].<ref name=combinedfleetI8/>

As Japanese military forces began to deploy for the opening Japanese offensive of the war, ''I-8'', with an embarked [[Watanabe E9W]]1 ([[World War II Allied names for Japanese aircraft|Allied reporting name]] "Slim") [[floatplane]], departed Saeki Bay on 11 November 1941 bound for [[Kwajalein Atoll]], which she reached on 20 November 1941.<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/> Assigned to support Operation Z, ''I-8'' got underway from Kwajalein on 24 November 1941 and set course for the [[Hawaiian Islands]].<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/> While she was en route, she received the message "Climb [[Yu Shan|Mount Niitaka]] 1208" ({{lang-ja|Niitakayama nobore 1208}}) from the [[Combined Fleet]] on 2 December 1941, indicating that war with the [[Allies of World War II|Allies]] would commence on 8 December 1941 [[Japan Standard Time|Japan time]], which was on 7 December 1941 on the other side of the [[International Date Line]] in [[Hawaii]].<ref name=combinedfleetI8/>

===World War II===

====First war patrol: Pearl Harbor====
By 7 December 1941, the day of the Pearl Harbor attack, ''I-8'' was patrolling north of [[Oahu]] with orders to attack any ships that attempted to [[sortie]] from Pearl Harbor.<ref name=combinedfleetI8/> She returned to Kwajalein on 24 December 1941.<ref name=ijnsubsiteI8/>

====Second war patrol====
''I-8'' got underway from Kwajalein again on 12 January 1942 bound for a patrol area off the [[United States West Coast]].<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/> Early on 3 February 1942, she arrived off [[San Francisco]], [[California]], and noted that the city did not appear to have instituted a [[Blackout (wartime)|blackout]].<ref name=combinedfleetI8/> Toward evening that day, she sighted a [[convoy]] of what she identified as seven [[Transport (ship)|transports]] and three [[destroyer]]s passing her at high speed, but she was unable to attempt an attack.<ref name=combinedfleetI8/> She had planned to use her floatplane for a reconnaissance flight over [[San Francisco Bay]], but rough weather forced her to cancel those plans.<ref name=combinedfleetI8/> She subsequently moved north along the U.S. West Coast as far as [[Seattle]], [[Washington (state)|Washington]], but found no opportunities to attack [[Allies of World War II|Allied ships]].<ref name=combinedfleetI8/> She discontinued her patrol on 9 February 1942 and headed for [[Kure, Hiroshima|Kure]], Japan, where she arrived on 2 March 1942.<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/><!--ijnsubite.com claims that I-8 called at Kwajalein on 1 February before proceeding to Kure, but a stop at Kwajalein then would have left little or no time on station of the U.S. West Coast and required her to make an exceptionally lengthy voyage from Kwajalein to Kure.-->

====March–September 1942====

After arriving at Kure, ''I-8'' began repairs and an overhaul.<ref name=combinedfleetI8/> After completion of the work, she departed [[Yokosuka]], Japan, on 15 April 1942 along with the rest of Submarine Squadron 3, bound for Kwajalein and serving as the squadron flagship with Rear Admiral Miwa embarked.<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/> During the squadron's voyage, it received orders on 18 April 1942 to search for a [[United States Navy]] [[task force]] reported to be operating {{convert|700|nmi}} east of [[Tokyo]], but it did not make contact with the task force.<ref name=combinedfleetI8/> The same day, 16 [[United States Army Air Forces]] [[North American B-25 Mitchell|B-25 Mitchell]] [[bomber]]s launched by the [[aircraft carrier]] {{USS|Hornet|CV-8}} — one of two aircraft carriers in the task force along with {{USS|Enterprise|CV-6}} — struck targets on [[Honshu]] in the [[Doolittle Raid]].<ref name=combinedfleetI8/>

The squadron resumed its voyage, but Rear Admiral Miwa became seriously ill.<ref name=combinedfleetI8/> While the other submarines of the squadron continued on to Kwajalein, ''I-8'' turned back for Yokosuka to seek medical treatment for him.<ref name=combinedfleetI8/> After she arrived at Yokosuka, Rear Admiral [[Chimaki Kono]] came aboard ''I-8'' and relieved Miwa as squadron commander, and ''I-8'' put back to sea on 26 April 1942 and again set course for Kwajalein.<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/><!--Combinedfleet.com claims I-8 departed Japan on 1 May 1942, but this departure date would not allow her to be off Roi-Namur in time for the friendly fire incident on 6 May 1942.--> She was off [[Roi-Namur]] at Kwajalein Atoll on 6 May 1942 when after 05:44 two Imperial Japanese Navy [[Mitsubishi G4M]]1 (Allied reporting name "Betty') [[bomber]]s mistook her for an Allied submarine and attacked her, dropping eight {{convert|60|kg|0|adj=on}} bombs and inflicting damage on ''I-8'' that prevented her from submerging.<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/> After calling at Kwajalein from 7 to 8 May 1942, she returned to Japan, arriving at Kure on 16 May 1942 for repairs.<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/> Because of the incident the Imperial Japanese Navy subsequently painted double white bands on its submarines, usually on the afterdeck, as a recognition aid.<ref name=combinedfleetI8/> 

On the day of her arrival at Kure, ''I-8'' was reassigned to Submarine Squadron 5.<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/> While ''I-8'' was in Japan, Submarine Squadron 5 was disbanded on 14 July 1942, and ''I-8'' was reassigned to serve as the flagship of the [[Southwest Area Fleet]] with the submarines of Submarine Division 30 — {{ship|Japanese submarine|I-162||2}}, {{ship|Japanese submarine|I-165||2}}, and {{ship|Japanese submarine|I-166||2}}.<ref name=combinedfleetI8/> ''I-8'' collided with the [[auxiliary cruiser]] {{ship||Bangkok Maru||2}} in Saeki Bay off the coast of Kyushu on 27 August 1942 and suffered minor damage.<ref name=combinedfleetI8/>

====Guadalcanal campaign====

The [[Guadalcanal campaign]] began with [[United States Marine Corps]] landings on [[Guadalcanal]] in the southeastern [[Solomon Islands (archipelago)|Solomon Islands]] on 7 August 1942.<ref name=combinedfleetI8/> Assigned directly to the 6th Fleet on 20 August 1942,<ref name=ijnsubsiteI8/> ''I-8'' departed Saeki, Japan, on 15 September 1942 to support Japanese forces in the campaign.<ref name=combinedfleetI8/> She arrived at [[Chuuk Atoll|Truk Atoll]] along with the submarines of Submarine Squadron 3 — {{ship|Japanese submarine|I-168||2}}, {{ship|Japanese submarine|I-169||2}}, {{ship|Japanese submarine|I-171||2}}, {{ship|Japanese submarine|I-172||2}}, {{ship|Japanese submarine|I-174||2}}, and {{ship|Japanese submarine|I-175||2}} — on 18 September 1942.<ref name=combinedfleetI8/><!--Combined Fleet asserts that all these submarines were a part of "Submarine Division 3" when they arrived at Truk on 18 September 1942, but ijnsubsite.com claims that I-8 was attached directly to the 6th Fleet until 1 April 1943 and that the other submarines were a part of Submarine Squadron (not Division) 3 at the time.--> She departed Truk later in September 1942 and conducted a war patrol in the southeastern Solomon Islands southeast of [[Makira|San Cristobal]], which she concluded with her arrival at the Japanese anchorage in the [[Shortland Islands]] on 2 October 1942.<ref name=ijnsubsiteI8/> She got back underway on 5 October for a war patrol in the vicnity of the [[Indispensable Reefs]] south of [[Rennell Island]], returning to the Shortlands anchorage on 24 October 1942.<ref name=ijnsubsiteI8/>

Later in October, ''I-8'' put to sea again for another patrol,<ref name=ijnsubsiteI8/> during which her Watanabe E9W1 (Allied reporting name "Slim") floatplane reconnoitered the harbors at [[Port Vila]] and [[Havannah (Efate)|Havannah]] on [[Efate]] in the [[New Hebrides]] on 2 November 1942.<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/> After returning to the Shortlands anchorage during November 1942, she loaded 21 tons of supplies for Japanese forces on Guadalcanal.<ref name=ijnsubsiteI8/> She departed the Shortlands on 4 December 1942 bound for Guadalcanal and, after delivering the supplies, returned to the Shortlands on 8 December 1942.<ref name=ijnsubsiteI8/>

During December 1942, ''I-8'' moved to Truk,<ref name=ijnsubsiteI8/> from which she got underway on 14 January 1943 for a war patrol in the [[Phoenix Islands]] off [[Canton Island]] and off the [[Samoan Islands]] and [[Fiji]].<ref name=ijnsubsiteI8/> During the patrol, she bombarded Canton Island twice with her {{convert|140|mm|in|adj=on|sp=us}} [[deck gun]]s, firing 41 rounds at the island on 23 January 1943<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/> and another 45 rounds on 1 February 1943.<ref name=ijnsubsiteI8/> 

While ''I-8'' was on patrol, the Guadalcanal campaign came to end with the evacuation of Japanese forces from the island in [[Operation Ke]], completed on 8 February 1943. ''I-8'' concluded her patrol with her arrival at Truk on 10 March 1943.<ref name=ijnsubsiteI8/> She then got back underway for an overhaul at Kure, which she reached on 21 March 1943.<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/>

====''Yanagi'' mission====
=====Voyage to France=====
The [[Tripartite Pact]] among the [[Axis Powers]] provided for an exchange of [[strategic material]]s and manufactured goods between [[Nazi Germany|Germany]], [[Fascist Italy (1922–1943)|Italy]], and Japan. At first, [[cargo ship]]s made voyages between Japan and Europe to exchange materials, but when that became impractical, submarines began to carry them out. The Japanese component of this submarine effort was known as the {{Nihongo|[[Yanagi missions|''Yanagi'' missions]]|柳作戦|Yanagi sakusen}}, or more formally the {{Nihongo|Submarine Missions to Germany|遣独潜水艦作戦|Kendoku sensuikan sakusen}}.  The first submarine to attempt a''Yanagi'' mission was {{ship|Japanese submarine|I-30||2}}, which made a trip from Japan to German-occupied [[France]] and back to [[Singapore]] between April and October 1942, but struck a British [[Naval mine|mine]] and sank before she could return to Japan.

While ''I-8'' was in Japan, her direct assignment to the 6th Fleet ended on 1 April 1943 when she was assigned to Submarine Division 14 in [[8th Submarine Squadron (Imperial Japanese Navy)|Submarine Squadron 8]] in the 6th Fleet.<ref name=ijnsubsiteI8/> With her overhaul complete, ''I-8'' was selected for the second ''Yanagi'' mission. Commanded by [[Captain (naval)|Captain]] Shinji Uchino, ''I-8'' conducted refueling exercises in the Iyo-nada in the [[Seto Inland Sea]] with the submarine {{ship|Japanese submarine|I-10||2}} from 17 to 19 May 1943.<ref name=combinedfleetI10>{{cite web |url= http://www.combinedfleet.com/I-10.htm |title=IJN Submarine I-10: Tabular Record of Movement |first1=Bob |last1=Hackett |first2=Sander |last2=Kingsepp |work=combinedfleet.com |date=March 18, 2017|access-date=21 December 2021}}</ref> Assigned directly to Submarine Squadron 8 on 25 May 1943,<ref name=ijnsubsiteI8/> she departed Kure on 1 June 1943<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/> accompanied by ''I-10'' and the submarine tender {{ship|Japanese submarine tender|Hie Maru||2}}.<ref name=combinedfleetI8/><ref name=combinedfleetI10/> Her cargo included two [[Type 95 torpedo|Type 95 oxygen-propelled torpedoes]], [[torpedo tube]]s, drawings of an automatic [[Dynamic trimming|trim]] system, and a new [[Yokosuka E14Y]] (Allied reporting name "Glen") reconnaissance floatplane. A supplementary crew of 48 men — commanded by [[Lieutenant commander|Lieutenant Commander]] Sadatoshi Norita and intended to man a German submarine, the [[Type IX U-boat|Type IXC/40]] [[U-boat]] {{GS|U-1224||2}}, and bring her back to Japan for [[reverse engineering]] — was also packed into the submarine, and a Constructor [[Commander (rank)|Commander]] Nishihara also made the voyage so that he could study German [[torpedo boat]] engines.<ref name=combinedfleetI8/> Norita's crew and Nishihara brought the number of men aboard ''I-8'' for the voyage to 160, creating very cramped conditions aggravated by the amount of cargo on board.<ref name=combinedfleetI8/> Most of Norita's men were accommodated in the forward torpedo room, and to make room for them, ''I-8'' carried only the six torpedoes loaded in her torpedo tubes during the voyage.<ref name=combinedfleetI8/>

The three vessels paused in [[Saeki Gulf]], then got back underway on 2 June 1943 to head south.<ref name=combinedfleetI10/> From 10 to 22 June, ''I-8'' called at [[Singapore]],<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/> where she took on board [[quinine]], [[tin]], and raw [[rubber]].<ref name=combinedfleetI8/> She arrived at [[Penang]] in Japanese-occupied [[British Malaya]] on 23 June 1943,<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/> With a cargo that also included [[tungsten]] and probably medicinal [[opium]],<ref name=combinedfleetI8/> she departed Penang on 27 June<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/> in company with ''I-10'' and headed across the [[Indian Ocean]], refueling from ''I-10'' at {{coord|04|53|S|087|20|E}} on 1 July and again at {{coord|22|25|S|076|15|E}} on 6 July 1943 before detaching from ''I-10'' and proceeding alone.<ref name=combinedfleetI8/><ref name=combinedfleetI10/> On 21 July 1943, ''I-8'' entered the [[Atlantic Ocean]] {{convert|300|nmi}} south of the [[Cape of Good Hope]] on the southern tip of [[Africa]].<ref name=combinedfleetI8/> Over the next ten days she encountered fierce storms which damaged her upper deck and aircraft [[hangar]] and was rarely able to make more than {{convert|5|kn}}.<ref name=combinedfleetI8/> During this time she received her first radio message from the German ''[[Kriegsmarine]]'', which provided warning of Allied air patrols and [[radar]] facilities.<ref name=combinedfleetI8/>

''I-8'' crossed the [[equator]] heading northward on 2 August 1943.<ref name=combinedfleetI8/> On 20 August, she rendezvoused with the German submarine {{GS|U-161|1941|2}} — under the command of ''[[Korvettenkapitän]]'' [[Albrecht Achilles (Korvettenkapitän)|Albrecht Achilles]] — in the Atlantic Ocean south of the [[Azores]], and an ''[[Oberleutnant zur See]]'' and two [[petty officer]]s transferred from ''U-161'' to ''I-8'' to install a [[radar detector]] — either a [[Metox radar detector|FuMB 1 Metox 600A]]{{citation needed|date=December 2021}} or a [[Wanze radar detector|FuMB 9 Wanze]],<ref name=combinedfleetI8/> according to different sources — on her [[Bridge (nautical)|bridge]],<ref name=combinedfleetI8/> which made ''I-8'' the first Japanese submarine with a radar detector.<ref name=combinedfleetI8/> ''I-8''′s crew presented ''U-161'' with a four-gallon tank of [[coffee]], and the two submarines parted company, with the three Germans remaining aboard ''I-8'' to guide her into port in German-occupied [[France]].<ref name=combinedfleetI8/> ''U-161'' was sunk with the loss of all 53 men on board on 27 September 1943, making them the only survivors of ''U-161''′s final patrol.<ref name=combinedfleetI8/>

[[File:I-8Brest.jpg|thumb|left|''I-8'' arriving at Brest, France]]
The Germans assigned ''I-8'' the code name ''Flieder'' ("[[Lilac]]").<ref name=combinedfleetI8/> After she entered the [[Bay of Biscay]] on 29 August 1943, the ''[[Luftwaffe]]'' sent [[Junkers Ju 88]] aircraft<ref name=combinedfleetI8/> of [[Kampfgeschwader 40|''Kampfgeschwader'' 40]]{{citation needed|date=December 2021}} to provide air cover. Several ''Kriegsmarine'' destroyers also escorted her as she approached [[Brest, France|Brest]], France.<ref name=combinedfleetI8/> After the German torpedo boats {{ship|German torpedo boat|T22||2}}, {{ship|German torpedo boat|T24||2}}, and {{ship|German torpedo boat|T25||2}} [[Minesweeping|swept]] a safe channel through the defensive field of magnetic influence mines protecting the harbor,<ref name=combinedfleetI8/> {{nowrap|''I-8''}} arrived at Brest safely on 31 August 1943,<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/> a German [[Tugboat|tug]] assisting her in docking in one of the [[submarine pen]]s there as a German [[military band]] played.<ref name=combinedfleetI8/>

=====In Europe=====
A German delegation led by the commander of the ''Kriegsmarine'''s ''Marineoberkommando der West'' ("Naval High Command of the West"), [[Admiral (Germany)|Admiral]] [[Theodor Krancke]], warmly greeted ''I-8''′s crew, which turned out on deck in their dress blue uniforms for the occasion, and presented them with German military decorations.<ref name=combinedfleetI8/> Over the next month, the Germans held parties for the Japanese and organized visits to [[Paris]] and [[Berlin]] for them.{{citation needed|date=December 2021}} The Germans also hosted the Japanese at a luxurious leisure facility at [[Chateau de Trévarez]], overlooking [[Chateauneuf de Faou]].<ref name=combinedfleetI8/> German news agencies highlighted ''I-8''′s visit, announcing that "now even Japanese submarines are operating in the Atlantic."{{citation needed|date=December 2021}}

For her return voyage, ''I-8'' loaded a cargo that included German equipment, including [[machine gun]]s, [[bomb sight]]s for horizontal bombers and [[dive bomber]]s, quad 20 mm [[anti-aircraft gun]]s, anti-aircraft [[gunsight]]s, a [[Daimler-Benz]] [[Daimler-Benz MB 501|MB 501]] 20-[[Cylinder (engine)|cylinder]] [[Diesel engine|diesel]] torpedo boat [[engine]] for German S-boats (known to the Allies as "[[E-boat]]s"),  [[marine chronometer]]s, radars, [[sonar]] equipment, and electric torpedoes,<ref name=combinedfleetI8/> as well as [[penicillin]].{{citation needed|date=December 2021}} As passengers she embarked Rear Admiral [[Tadao Yokoi]], the Japanese [[naval attaché]] to Berlin since 1940; Captain [[Sukeyoshi Hosoya]], the Japanese naval attaché to France since December 1939; three German naval officers; four German radar and [[hydrophone]] technicians; and four German civilians.<ref name=combinedfleetI8/>

=====Return to Japan=====
''I-8'' departed Brest on 5 October 1943<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/> with a strong escort of ''Kriegsmarine'' vessels.<ref name=combinedfleetI8/> After crossing the equator southbound, she sent the second position report of her voyage to the ''Kriegsmarine''.<ref name=combinedfleetI8/> Allied [[signals intelligence]] detected her transmission and used [[high-frequency direction finding]] to plot her position.<ref name=combinedfleetI8/> The next day, an Allied [[Antisubmarine warfare|antisubmarine]] aircraft attacked her, but she escaped by [[Crash dive|crash-diving]].<ref name=combinedfleetI8/>

''I-8'' encountered another storm while passing through the "[[Roaring Forties]]" which delayed her and damaged her bridge.<ref name=combinedfleetI8/> By November 1943 she had reached the Indian Ocean, where she affixed the ''[[hinomaru]]'' national identification marking to her [[conning tower]] just as a Japanese plane buzzed her, possibly avoiding a mistaken attack by the aircraft.<ref name=combinedfleetI8/> Crtically low on fuel, she attempted to contact the Japanese base at Penang and other Japanese submarines for assistance, but without success.<ref name=combinedfleetI8/> She nonetheless arrived safely at Penang on 2 December 1943.<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/> Departing Penang on 4 December 1943,<ref name=ijnsubsiteI8/> she reached Singapore on 5 December,<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/> and Kure on 21 December 1943<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/> after a round-trip voyage of {{convert|30000|nmi|-3}}.<ref name=combinedfleetI8/> She subsequently moved to the [[Tamano]] Shipyard in [[Okayama Prefecture]] for a refit.<ref name=combinedfleetI8/>

One of only seven submarines, and one of only five Japanese submarines, to attempt a voyage between Japan and Europe during World War II, ''I-8'' gained the distinction of becoming the only submarine to complete a round trip between Japan and Europe during the war.<ref name=combinedfleetI8/> In addition to ''I-30'', sunk in the only ''Yanagi'' mission prior to ''I-8''′s voyage, the three submarines which attempted ''Yanagi'' missions after ''I-8'' — {{ship|Japanese submarine|I-34||2}} , sunk by the [[Royal Navy]] submarine {{HMS|Taurus|P399|6}} on 13 November 1943;  {{ship|Japanese submarine|I-52|1943|2}}, sunk by U.S. Navy aircraft on 24 June 1944; and {{ship|Japanese submarine|I-29||2}}, sunk by the U.S. Navy submarine {{USS|Sawfish|SS-276}} on 26 July 1944 — all were lost during their voyages. Of the two German submarines that attempted Europe-to-Japan trips analogous to the Japanese ''Yanagi'' missions, {{GS|U-511||2}} made only a one-way trip, being sold to the Imperial Japanese Navy after her arrival in Japan in September 1943, and {{GS|U-180||2}} was sunk on only the third day of her outbound voyage in August 1944.

====War crimes under Ariizumi====
While ''I-8'' was in Japan, she received a new crew, and Commander [[Tatsunosuke Ariizumi]] became her new commanding officer on 15 January 1944.<ref name=combinedfleetI8/> ''I-8'' subsequently gained infamy for [[war crime]]s during the war patrols she conducted under his command because of his and his crew's treatment of Allied [[Prisoner of war|prisoners-of-war]].<ref name=shipsfromhell>Ships from Hell: Japanese War Crimes on the High Seas in World War II, Raymond Lamont-Brown, The History Press, 2013, {{ISBN|075249483X}}, 9780752494838</ref>

=====Ariizumi's first war patrol: SS ''Tjisalak''=====
''I-8'' departed Kure on 21 February 1944 and proceeded to Penang,<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/> which she reached on 10 March 1944.<ref name=ijnsubsiteI8/> She got underway from Penang on either 15<ref name=combinedfleetI8/> or 19<ref name=ijnsubsiteI8/> March 1944 (sources disagree) for a war patrol in the Indian Ocean off the [[Maldive Islands]].<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/>

On 26 March 1944, ''I-8'' torpedoed the [[Netherlands|Dutch]] 5,787-[[gross register ton]] armed cargo ship {{SS|Tjisalak}}.<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/><ref name=shipsfromhell/> Shortly thereafter, ''I-8'' surfaced amid the debris field, and after a brief exchange of gunfire with the sinking ship, collected the 97<ref name=shipsfromhell/> or 103<ref name=combinedfleetI8/> survivors (sources disagree) on the submarine's deck.<ref name=shipsfromhell/> Shortly after ''Tjisalak'' sank<ref name=combinedfleetI8/> south of [[Colombo]], [[Ceylon]], at {{coord|02|30|S|078|40|E|name=SS ''Tjisalak''}},<ref name=ijnsubsiteI8/> ''I-8''′s crew tied her crew and passengers in pairs and attacked them, slashing them with [[Shin guntō|swords]] and beating them with [[monkey wrench]]es and [[sledgehammer]]s before shooting them and kicking them overboard. Those who jumped overboard were machine-gunned in the water.<ref name=combinedfleetI8/> Only five<ref name=combinedfleetI8/> or six<ref name=shipsfromhell/> men (sources disagree) survived the massacre; they found a [[life raft]]<ref name=shipsfromhell/> or [[Lifeboat (shipboard)|lifeboat]]<ref name=combinedfleetI8/> (sources disagree) and the American [[Liberty ship]] {{SS|James O. Wilder||6}} later rescued them.<ref name=combinedfleetI8/><ref name=shipsfromhell/>

On 30 March 1944, ''I-8''′s Watanabe E9W1 (Allied reporting name "Slim") floatplane sighted the British 6,589-gross register ton armed [[merchant ship]] {{SS|City of Adelaide|1920|6}} in the Indian Ocean southeast of  [[Diego Garcia]] in the [[Chagos Archipelago]] during a reconnaissance flight.<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/> The plane vectored ''I-8'' to intercept ''City of Adelaide'' — which was steaming independently in ballast from [[Karachi]] in [[British Raj|British India]] to [[Fremantle]], [[Australia]] — then returned to ''I-8''.<ref name=combinedfleetI8/> After dark, ''I-8'' fired one torpedo at ''City of Adelaide'' which struck her amidships.<ref name=combinedfleetI8/> She took on a heavy [[Angle of list|list]] and, after transmitting a [[distress signal]], her crew and gunners abandoned ship.<ref name=combinedfleetI8/> ''I-8'' then surfaced and sank ''City of Adelaide'' with gunfire at {{coord|12|01|S|080|27|E}}.<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/>

At 06:07 on 11 April 1944, a Japanese submarine — apparently ''I-8'' — fired four torpedoes about four minutes apart at the American armed [[T2 tanker]] {{SS|Yamhill}} in the Indian Ocean at {{coord|03|31|N|067|07|E}}.<ref name=combinedfleetI8/> Two of the torpedoes passed along each side of ''Yamhill''.<ref name=combinedfleetI8/> ''Yamhill'', which was on a voyage from [[Bahrain]] to Fremantle with a cargo of oil intended for use by U.S. Navy submarines, reported that she was under submarine attack and requested air cover.<ref name=combinedfleetI8/> The submarine surfaced about {{convert|11,000|yd|m|sigfig=3}} from ''Yamhill'' and a 12-hour chase ensued in which the vessels exchanged fire, ''Yamhill''′s {{convert|5|in|mm|adj=on|sigfig=3}} gun outranging the submarine's {{convert|140|mm|in|1|adj=on|sp=us}} gun by about {{convert|175|yd|0}}.<ref name=combinedfleetI8/> At around sundown, after the submarine had fired about 20 rounds and ''Yamhill'' had fired 38, a [[Royal Air Force]] [[Consolidated PBY Catalina|Catalina]] [[flying boat]] arrived and forced the submarine to submerge, allowing ''Yamhill'' to escape in the growing darkness.<ref name=combinedfleetI8/>

On 16 April 1944, ''I-8'' sank a [[sailing vessel]] with gunfire off [[Addu Atoll]] in the Maldives.<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/> She concluded her patrol on 5 May 1944 with her return to Penang.<ref name=ijnsubsiteI8/>

=====Ariizumi's second war patrol: SS ''Jean Nicolet''=====
''I-8'' began her next war patrol on 10 June 1944, assigned a patrol area in the Indian Ocean off [[Madagascar]].<ref name=ijnsubsiteI8/> While en route, she torpedoed the British 6,942-gross register ton armed [[Cargo liner|passenger-cargo ship]] ''Nellore'' — which was n a voyage from [[Bombay]] in British India to [[Sydney]], Australia, carrying 174 passengers and 2,720 tons of general cargo including government stores — in the Indian Ocean southwest of Diego Garcia at {{coord|07|51|S|075|20|E}} at 23:45 on 29 June 1944.<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/> Two torpedoes struck ''Nellore'', which caught fire and went dead in the water,<ref name=combinedfleetI8/> and her survivors abandoned ship in nine lifeboats.<ref name=combinedfleetI8/> ''I-8'' surfaced and brought aboard 11 of the survivors — a gunner and 10 passengers,<ref name=combinedfleetI8/> — and then sank the blazing ''Nellore'' with gunfire at around 02:45 on 30 June 1944.<ref name=combinedfleetI8/> A total of 79 people from ''Nellore'' — 35 crew members, five gunners, and 39 passengers — lost their lives before the Royal Navy [[frigate]] {{HMS|Lossie|K303}} and a Royal Air Force [[seaplane]] rescued her remaining survivors.<ref name=combinedfleetI8/> Several of ''Nellore''′s survivors mistakenly claimed that she had been sunk in an attack by as many as three German submarines.<ref name=combinedfleetI8/>

On 2 July 1944, ''I-8'' was involved in another atrocity when she struck the American 7,176-gross register ton Liberty ship {{SS|Jean Nicolet}} — bound from Bombay to Sydney with a cargo of war materials — with two torpedoes in her [[Port and starboard|starboard]] side in the Indian Ocean {{convert|700|nmi|sigfig=2}} off the Maldives south of [[Ceylon]].<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/> Shortly after the torpedoes hit, ''Jean Nicolet''′s 100 crewmen abandoned ship and took to her lifeboats. ''I-8'' surfaced and opened gunfire on ''Jean Nicolet'', which caught fire before sinking at {{coord|03|28|S|074|30|E|name=SS ''Jean Nicolet''}}.<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/> ''I-8'' took 99 survivors aboard.<ref name=combinedfleetI8/>

Again, ''I-8''′s crew gathered the survivors on her deck and searched, bound, and questioned them.<ref name=combinedfleetI8/> Ariizumi ordered ''Jean Nicolet''′s [[Sea captain|master]] and [[radio]] operator and a civilian passenger taken below, and ''I-8''′s crew then began a massacre of the others. The massacre took several hours, as the Japanese made the survivors walk one at a time past the [[conning tower]], where they were murdered.<ref>{{Cite web|url=http://www.armed-guard.com/ag87.html|title=Moore|website=www.armed-guard.com}}</ref> Most were beaten, some were stabbed, one was shot, and some were forced to run a gauntlet of ''I-8'' crewmen who attacked them with knives and pipes.<ref name=combinedfleetI8/> Meanwhile, ''I-8''′s crew also destroyed ''Jean Nicolet''′s lifeboats with gunfire.<ref name=combinedfleetI8/> When ''I-8''′s radar detected an approaching aircraft, she submerged with the remaining ''Jean Nicolet'' survivors, still bound, on deck, plunging them into the ocean, where most drowned.<ref name=combinedfleetI8/> Sources differ, but it is believed 23 men made it to a life raft, from which they were picked up by the [[armed trawler]] {{HMS|Hoxa|T16|6}} 30 hours later, although one source<ref name=combinedfleetI8/> claims that only four men survived. ''I-8'' took five prisoners from ''Jean Nicolet'' to Japan where one of them, Francis J. O'Gara, was found alive in a [[prisoner-of-war camp]] after World War II. A new Liberty ship, {{SS|Francis J. O'Gara}}, had been named after him by that time, making O'Gara the only living person to have a Liberty ship named after him.<ref>{{Cite web|url=http://geocities.com/Pentagon/Camp/3166/|archive-url=https://web.archive.org/web/20091027051402/http://geocities.com/Pentagon/Camp/3166/|url-status=dead|archive-date=27 October 2009|title=Submarine Atrocities|date=27 October 2009}}</ref>

''I-8'' concluded her patrol with her arrival at Penang on either 8<ref name=combinedfleetI8/> or 14<ref name=ijnsubsiteI8/> August 1944, according to different sources.

=====August–November 1944=====

When the German submarine {{GS|U-862||2}} arrived at Penang on 9 September 1944, Ariizumi joined the commander — Rear Admiral [[Jisaku Ouzumi]] — and staff of Submarine Squadron 8 in welcoming the German crew.<ref name=combinedfleetI8/> On 11 September 1944, ''U-862'' hosted a visit by Ouzumi, Arriizumi, and ''I-8''′s officers, and later that day ''U-862''′s commanding officer, ''Korvettenkapitän'' [[Heinrich Timm]], and his officers visited ''I-8''.<ref name=combinedfleetI8/>

''I-8'' departed Penang later in September 1944<ref name=ijnsubsiteI8/> and arrived on 9 October 1944 at Yokosuka,<ref name=ijnsubsiteI8/><ref name=combinedfleetI8/> where she underwent a refit, repairs, and modifications, including the removal of her hangar and [[aircraft catapult]] and their replacement with fittings for ''[[kaiten]]'' manned [[suicide attack]] torpedoes.<ref name=combinedfleetI8/> On 5 November 1944, Ariizumi relinquished command for a new assignment.<ref name=combinedfleetI8/>

=====Postwar prosecution of crew=====
The high or total loss of life aboard merchant ships ''I-8'' sank while Ariizumi was in command suggested to Allied investigators that Ariizumi and his men may have committed additional [[war crimes]] beyond those documented in the ''Tjisalak'' and ''Jean Nicolet'' incidents.{{citation needed|date=December 2021}} Ariizumi, who had encouraged and participated in the murders, had reached the rank of captain and was the commander of Submarine Division 1 when he committed suicide aboard his flagship, the submarine {{ship|Japanese submarine|I-401||2}}, while she was in the [[Philippine Sea]] on 30 August 1945 and making her way to Japan to surrender to the Allies in the immediate aftermath of the cessation of hostilities.<ref>{{cite web |url= http://www.combinedfleet.com/I-401.htm |title=IJN Submarine I-401: Tabular Record of Movement |first1=Bob |last1=Hackett |first2=Sander |last2=Kingsepp |work=combinedfleet.com |date=March 22, 2011|access-date=22 December 2021}}</ref> Few of ''I-8''′s crew during his time in command had survived the war, but Allied investigators located three of them after the war and prosecuted them.{{citation needed|date=December 2021}} One, found in the United States, was granted immunity in return for testifying against his former comrades and was then allowed to return to the United States.{{citation needed|date=December 2021}} The others were convicted and served prison terms, which the [[Government of Japan|Japanese government]] [[Commutation (law)|commuted]] in 1955.{{citation needed|date=December 2021}}

====Okinawa campaign====

Despite her new ''kaiten'' fittings, ''I-8'' had no ''kaiten'' on board when she departed Saeki with the submarines {{ship|Japanese submarine|Ro-41||2}}, {{ship|Japanese submarine|Ro-49||2}}, and {{ship|Japanese submarine|Ro-56|1944|2}} on 18 March 1945 to operate south of [[Okinawa]].<ref name=combinedfleetI8/> She returned to Saeki on 19 March for repairs,<ref name=ijnsubsiteI8/> but again got underway on 20 March 1945<ref name=ijnsubsiteI8/> to begin her patrol. The preliminaries of the [[Battle of Okinawa|Okinawa campaign]] began on 26 March 1945, when American forces began landing on the [[Kerama Islands]].<ref name=combinedfleetI8/> At 18:05 on 28 March 1945, she transmitted a message reporting that she had sighted two Allied transports and four destroyers {{convert|110|nmi}} from [[Naha]], bearing 150 degrees.<ref name=combinedfleetI8/> The Japanese never heard from her again.

====Loss====
On 31 March 1945, the U.S. Navy destroyer {{USS|Stockton|DD-646}} detected a surface target on radar while screening a [[task group]] off the Kerama Islands.<ref name=combinedfleetI8/> She approached the contact, which turned out to be ''I-8''.<ref name=combinedfleetI8/> ''I-8'' crash-dived, after which ''Stockton'' made sonar contact on her.<ref name=combinedfleetI8/> Over the next four hours, ''Stockton'' expended all of her [[depth charge]]s in seven attacks against ''I-8''.<ref name=combinedfleetI8/>

''I-8'' surfaced just as the destroyer {{USS|Morrison|DD-560}} arrived on the scene to reinforce ''Stockton''.<ref name=combinedfleetI8/> ''I-8'' immediately submerged again, but ''Morrison'' dropped a pattern of depth charges that forced ''I-8'' to surface {{convert|900|yd|m|sigfig=2}} from ''Morrison''.<ref name=combinedfleetI8/> After a 30-minute exchange of gunfire, ''I-8'' [[capsize]]d and sank by the [[stern]] in the [[Philippine Sea]] at {{coord|25|29|N|128|35|E|name=''I-8''}}.<ref name=combinedfleetI8/> One of ''Morrison''′s boats picked up an unconscious petty officer who had been a member of ''I-8''′s gun crew, and he was ''I-8''′s only survivor.<ref name=combinedfleetI8/>

On 10 April 1945, the Imperial Japanese Navy declared ''I-8'' to be presumed lost in the Okinawa area.<ref name=combinedfleetI8/> The Japanese struck her from the navy list on 10 August 1945.<ref name=combinedfleetI8/>

==Notes==
{{Reflist}}

==References==
{{Cite book|last=Bridgland |first=Tony |title=Waves of Hate |year=2002 |publisher=Pen & Sword |isbn=0-85052-822-4 }}

==External links==
* [http://piquetjm.ns5-wistee.fr/cybervillage/viewtopic.php?t=365 Article with pictures of I-8 stay in France from a Kriegsmarine reel (French text) from www.lazaloeil.com ]

{{Junsen type submarine}}
{{May 1942 shipwrecks}}
{{August 1942 shipwrecks}}
{{March 1945 shipwrecks}}
{{Use dmy dates|date=August 2019}}

{{DEFAULTSORT:I-008}}
[[Category:Type J3 submarines]]
[[Category:Junsen type submarines]]
[[Category:Ships built by Kawasaki Heavy Industries]]
[[Category:1936 ships]]
[[Category:World War II submarines of Japan]]
[[Category:Maritime incidents in March 1945]]
[[Category:Friendly fire incidents of World War II]]
[[Category:Japanese war crimes]]
[[Category:Japanese submarines lost during World War II]]
[[Category:Submarines sunk by United States warships]]
[[Category:World War II shipwrecks in the Philippine Sea]]