'Stultify' was a British deception plan for 'Extended Capital' (1944/45).
The 'story' promulgated by 'Stultify', which replaced 'Flabbergast', was that Admiral the Lord Louis Mountbatten’s South-East Asia Command planned to undertake the recapture of Akyab island in the Arakan western coastal region of Burma at a time early in February 1945, and then in March or April to attempt a combined operation to take a position running from the lower reaches of the Irrawaddy river at Prome to the coast at Taungup as the start line for a later overland advance to Rangoon. This was to be supported by 'a cautious but much publicized overland advance' (in fact the real 'Extended Capital') in northern and central Burma, and to be followed in April by an operation to seize naval and air bases in the north-western part of the island of Sumatra in the Dutch East Indies in order to retake and immediate developing the strategically important rubber-producing areas, followed by an eastward exploitation to the neighbouring major island of Java.
Subsidiary undertakings, known collectively as 'Knockout' (ii), were 'Fang', 'Claw', 'Caption', 'Araminta' and 'Wolf'. 'Stultify' was later merged into 'Sceptical' (i).