3. The heavy bombers could operate against Malaya and the Kra Isthmus from the recently acquired air bases in South Indo-China, but any attack against Singapore itself would be at extreme range with normal bomb load. The light bombers could probably only operate effectively from aerodromes in Central Thailand and the Northern part of the Kra Isthmus after these have been taken over by the Japanese. 4. It is thought that the Japanese would feel compelled to retain a large proportion of their most modern type of aircraft to oppose the Russians in Siberia and that accordingly the aircraft used against Malaya and the Kra Isthmus would include a number of less modern types.