(KS type RO-109 scanned from "Submarines of the Imperial Japanese Navy" by Polmar and Carpenter)

IJN Submarine RO-103:
Tabular Record of Movement

2001-2012 Bob Hackett & Sander Kingsepp
Revision 2

30 June 1941:
Kure. Laid down at Kure Navy Yard as 525-ton (standard) Kaisho (KS) Type submarine No. 213.

6 December 1941:
Launched as RO-103.

25 July 1942:
Lt Sakamoto Kaneyoshi (61)(former Torpedo/Division Officer of I-1) Chief Equipping Officer of RO-100, also under construction at Kure, is posted additional duty as Chief Equipping Officer for RO-103.

29 August 1942:
Lt Fujita Hidenori (62) is posted Chief Equipping Officer.

21 October 1942:
Completed and assigned to Kure SubRon. Lt Fujita is the CO. Assigned to Kure SubRon.

5 January 1943:
Reassigned to Rear Admiral (later Vice Admiral) Harada Kaku's (former CO of CVS CHIYODA) SubRon 7 in SubDiv 13 of Vice Admiral Mikawa Gunichi's (former CO of KIRISHIMA) Eighth Fleet at Rabaul. Departs Kure.

14 January 1943:
Arrives at Truk.

4 February 1943:
Departs Truk.

8 February 1943:
Arrives at Rabaul.

9 February 1943:
Departs Rabaul on her first war patrol with RO-102 to patrol E of Port Moresby, New Guinea.

16 February 1943:
Lt Ichimura Rikinosuke (64)(former navigating officer of RO-100) is appointed the next CO.

28 February 1943:
Returns to Rabaul.

2 March 1943: The Battle of the Bismarck Sea:
A convoy of Supply Operation No. 81 under Rear Admiral (later Vice Admiral) Kimura Masatomi (former CO of SUZUYA) is en route to Lae, New Guinea with troops of the IJA's 51st Division embarked. Over the next three days, the convoy is bombed and strafed repeatedly by USAAF and RAAF planes. All of the eight transports and cargo vessels in the convoy and four of the eight escorting destroyers are sunk. Hundreds of IJA soldiers in lifeboats, rafts and in the water are machine-gunned by planes and PT boats.

10 March 1943:
Ichimura spots an American destroyer. He orders all classified documents dumped in the sea, but the destroyer turns away without spotting RO-103.

13 March 1943:
RO-103 is dispatched to rescue survivors of Kimura's convoy.

15 March 1943:
RO-103 runs aground on an uncharted reef at 08-20S, 150-45E. Fujita signals Rabaul for assistance. RO-101 is ordered to the scene to tow. RO-103 dumps food, supplies and torpedoes to lighten the submarine. She breaks free from the reef before RO-101 arrives.

17 March 1943:
Returns to Rabaul.

30 March 1943: Operation "I-GO" - The Reinforcement of Rabaul.
Admiral (Fleet Admiral, posthumously) Yamamoto Isoroku (former CO of AKAGI), CINC Combined Fleet, orders aircraft from CarDiv 1's ZUIKAKU and ZUIHO to reinforce Vice Admiral Kusaka Jinichi's (former CO of FUSO) 11th Air Fleet's base at Rabaul. Yamamoto also orders aircraft from CarDiv 2's HIYO and JUNYO to reinforce the base at Ballale Island, near Buin, Bougainville.

Departs Rabaul on her second war patrol for the Guadalcanal area with RO-102 to support I-GO.

20 April 1943:
Returns to Rabaul.

9 May 1943:
Departs Rabaul to patrol off in an area E of Guadalcanal on her third war patrol.

1 June 1943:
Returns to Rabaul.

12 June 1943:
Departs Rabaul for the Gatukai-San Cristobal area on her fourth patrol.

23 June 1943:
50 nms S of the eastern tip of the San Cristobal Island. Lt Ichimura sights a convoy of three transports protected by three destroyers. He torpedoes and sinks 7,440-ton USS ALDURA (AK-72) and torpedoes 7,176-ton "Liberty" ship USS DEIMOS (AK-78), while both are in convoy en route to Guadalcanal in the vicinity of 11-26S, 162-01E at the eastern tip of San Cristobal Island. DEIMOS, damaged irreparably, is scuttled by destroyer O'BANNON (DD-450) at 11-35S, 162-08E.

29 June 1943:
While recharging batteries after sunset, Lt Ichimura reports sighting seven enemy ships S of Gatukai Island. These are probably ships of Rear Admiral (later Admiral) Richmond K. Turner's Third Fleet's Amphibious Force.

30 June 1943: American Operation "TOENAILS" - The Invasion of New Georgia, Solomons:
Rear Admiral (later Admiral) Richmond K. Turner's Third Fleet Amphibious Force, supported by land-based aircraft, lands Marines and Army troops on Rendova and other islands in the New Georgia area.

4 July 1943:
Returns to Rabaul.

11 July 1943:
Departs Rabaul on her fifth war patrol for the Rendova area.

13 July 1943:
Arrives at her patrol area at Vanga Bay, Vangunu Island.

15-24 July 1943:
Lt Ichimura sights enemy forces three times, but is unable to gain an attack position.

28 July 1943:
N of New Georgia, Bismarck Islands. Ichimura reports his three enemy ship sightings to Rabaul. It is the last signal received from RO-103. [1]

10 August 1943:
Presumed lost with all 43 hands in the Solomons Lt Ichimura is posthumously promoted LtCdr.

1 November 1943:
Removed from the Navy List.

Authors' Notes:
[1] The circumstances surrounding the loss of RO-103 remain unknown - perhaps she was sunk by a mine or a PT-boat. Author/historian Kimata Jiro suggests she hit a mine in one of the mine fields laid by USS BREESE (DM-18), PREBLE (DM-20) and GAMBLE (DM-15).

Thanks go to Dr. Higuchi Tatsuhiro of Japan and Matt Jones of the USA.

Bob Hackett and Sander Kingsepp.

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