AIR FORCES 14. Although the estimates given below have been based on two alternatives, one of which is that Russia. has entered the war, it is impossible to estimate and so take into account the effect of heavy losses which might, as a result, have been incurred by the Japanese if Russia's entry into the war had preceded by an appreciable time the dates of the attack on North Borneo dealt with below. If these losses had in fact been heavy, the Japanese might have been compelled so fundamentally to alter their strategy as to withdraw all their air forces to the Inner Zone from the Burma-Malaya-Siam-South Indo-China-East Indies area.