Japanese Security Service home organisation

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Japanese Security Service home organisation

Kaoru Matusomoto (KV 2/2469-2471)

These three files give an unusual insight into the career of Matusomoto, a Japanese diplomat in London until he was interned in December 1941. By all accounts an intelligent and urbane character, Matusomoto was suspected of using his role as a cultural attaché in London as a cover for using funds from the Japanese secret vote to recruit agents in Britain. Though this seemed to be fully believed at the time, minuting added to the file after its closure in the 1970s suggests that in fact he may not have been an intelligence officer at all. There is much intercepted correspondence on the file about Matusomoto's views on the progress and conduct of the war.

KV 2/2469 (1940-1941) starts with Matusomoto's arrival in Southampton in May 1940, and includes output of the telephone checks mounted on him. The file shows his assiduous development of society contacts (including one suspected intimate relationship with Lady Patricia French). By June 1941 Security Service staff were minuting confidently that there was incontrovertible evidence that Matusomoto was "engaged in intelligence work" (e.g. serial 54a). The file includes reports of his meetings with Douglas Jay.

Matusomoto was interned in December 1941 (see KV 2/2470, 1941-1942) in direct retaliation for the arrest of British diplomat H V Redman in Tokyo. An account of his arrest is at serial 131a, and a report of his interview at the Oratory School internment centre is at serial 131b. While interned, Matusomoto became acquainted with the interned future Security Service agent Kuchnekoff, and their varying accounts of their relationship constitute much of the interest in KV 2/2471 (1942-1946, with later additions). Matusomoto asked Kuchnekoff to smuggle out a letter to his father when he knew Kuchnekoff was to be freed from internment, and a translation giving a detailed account of his life and treatment in internment is included on the file (serial 152a).

Matusomoto was repatriated in an exchange deal in 1943, and he rejoined the Japanese foreign ministry. Subsequent interrogation reports taken at Changi jail in Singapore are included towards the end of the file.

Japanese Security Service home organisation (KV 3/295-297)

These three files document the extent of British knowledge of the Japanese intelligence organisation before and during the Second World War, along with some post-war assessments, and concerns in the 1950s about the re-emergence of Japanese intelligence activities.  The formal organisation is noted as being one that depended largely on the diplomatic establishment for its overseas coverage, with the result that at the outbreak of war, the organisation largely collapsed in Allied countries. The files also note that there was great reliance on civilian Japanese overseas acting almost as amateur spies to provide intelligence.

KV 3/295 (1936-1945) includes coverage of the spy phobia that gripped Japan in the mid 1930s and saw the arrest of several Britons. There is a copy of the Far East Combined Bureau bulletin on Japanese intelligence at serial 29ab, and a 1945 note summarising the work of the intelligence organisation after the attack on Pearl Harbour to the end of the war in serial 46a. This file includes correspondence by Anthony Blunt, who was involved in some aspects of monitoring Japanese intelligence work.

Post-war work to gather information on wartime activities can be found in KV 3/296 (1945-1947), which includes The Security Service's Director-General David Petrie's minuted comments on Japanese intelligence capabilities: "…the picture in whole and in parts is a somewhat confused one, puzzling at times even the Japanese themselves…Everything was made too easy for them and they did not fail to profit by it." (minute 56). The file includes correspondence on Japanese secret writing techniques.

KV 3/297 (1949-1955) covers the re-emergence of supposed Japanese intelligence activities in the Far East from around 1954.