Hut 7

Hut 7 was a wartime section of the Government Code and Cypher School (GC&CS) at Bletchley Park tasked with the solution of Japanese naval codes such as JN4, JN11, JN40, and JN25. The hut was headed by Hugh Foss who reported to Frank Birch, the head of Bletchley's Naval section.

Hut 7 supplied cryptanalysts and linguists to Bletchley’s front line station the Far East Combined Bureau (FECB) at Hong Kong, then Singapore, then Anderson Station (Colombo, Ceylon, now Sri Lanka), then Allidina School in Kilindini, Kenya before moving back to Colombo.

Bletchley co-operated with the US Navy Code and Signals Section known as OP-20-G in Washington D.C., and with FRUMEL in Melbourne (although the reciprocal cooperation from Fabian at FRUMEL was limited and reluctant).

Among the first challenges was overcoming the special kana and romaji Morse code system used by the Japanese. GC&CS began breaking Japanese diplomatic traffic in the early 1920s. GC&CS subsequently attacked the Naval Reporting Code, and General Operations Code.

The section was headed by William "Nobby" Clarke with Harry Shaw and Ernest Hobart-Hampden. These were later joined by Eric Nave, seconded from the Royal Australian Navy, John Tiltman, and Hugh Foss.

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