senior cryptographer in the US Army Signals Intelligence Service under William F. Friedman. Sinkov had previously been in charge of an intercept station in Panama. He had visited Britain in 1941 to facilitate the exchange of cryptographic information. With Sinkov (US Army), the three assistant directors were Australians Alistair "Mic" Sandford (Major then Lt-Col, Second AIF) and Roy Booth (Squadron Leader then Wing Commander, RAAF). They acted as head of their respective service organisations; with Sandford the bureau executive officer under Sherr, then Booth from 1944. The bureau functioned well and harmoniously, with job demarcation as Australian experience was from wireless interception and traffic analysis in the Middle East and the Americans in breaking codes and cyphers, although this "broke down" as the war went on. Signals organisations tend to be "meritocratic" rather than on rank. Experienced intercept Kana operators from a Royal Australian Air Force unit at Townsville were assigned to the new Central Bureau. The RAAF at the time had a number of Kana operators being trained and were about to train a further 13 WAAAF personnel. (Katakana is one of the syllabic forms of written Japanese). The cryptanalysts who had operated from the Malinta Tunnel during the Battle of Corregidor got out to Australia by submarine in two groups. Their equipment was pushed into Manila Bay. They were used to assist the Australian Wireless Group units. A group of cryptographic, cryptanalytic and translator personnel from the Japanese section of the Washington Signal Intelligence Service were also moved to Australia. More Australians were also recruited to Central Bureau after it was established. Structure Central Bureau comprised: administrative personnel supply personnel cryptographic personnel cryptanalytic personnel interpreters translators a field section which included the intercept and communications personnel On 25 April 1942 the small RAAF Intercept Station operating in two back-to-back houses at 21 Sycamore Street and 24 French Street in the suburb of Pimlico in Townsville was given its new name of No. 1 Wireless Unit and became part of Central Bureau. The newly named Unit included 7 RAAF, 1 AMF and 4 United States Army personnel in No. 1 Wireless Unit at Townsville. This RAAF Unit had started earlier in March 1942 as a small intercept station located in the initial two houses at Pimlico under Wing Commander Booth. By 6 July 1942 the intercept operator numbers at Central Bureau had increased from six to twenty nine. Commander