This was a British deception undertaking seeking to persuade the Japanese that a major amphibious descent on Sumatra, in the occupied Netherlands East Indies, was imminent (1944/45).
Conceived as part of 'Stultify' and thus related to 'Araminta', 'Caption', 'Claw' and 'Wolf' (v), the undertaking was originally to have been allocated to a 12th Army, Brigadier Dudley W. Clarke’s long-running fake headquarters in the Middle East, which had notionally been transferred to India at the time the 'Wantage' order of battle was brought to an end. But with the activation of a real 12th Army as successor to the 14th Army, the command for 'Fang' became the Indian Expeditionary Force. This comprised two fictional major formations, in the form of the the amphibious Indian XXXVIII Corps based in Ceylon under the notional command of Major General C. E. N. Lomax, who was well known to the Japanese as the former commander of the real Indian 26th Division, and the Indian XX Corps, notionally commanded for a brief period by Lieutenant General G. W. R. Templer and then by Lieutenant General W. H. A. Bishop. Like both of these corps, al of their constituent formations and units imaginary: some of them were 'Wantage' divisions supposedly transferred from the Middle East. The original launch date for 'Fang' was 30 April 1945, but this date naturally saw various 'postponements' and was finally overtaken by the end of the war.