In making plans for war, the Japanese coveted the tin and rubber of Malaya. The islands were rich in resources, and nearby Java had badly needed oil. The American embargo had left Japan with enough oil to last through 1944 if consumption was reduced.
Malaya was the victim of interservice rivalry between the United Kingdom forces assigned to defend it. 15-inch guns and 88,000 men defended the "Gibraltar of the East", but they were undersupplied, only had anti-ship ammunition, and could not turned against the jungle roads. The 158 aircraft of the RAF were based on airstrips that the Army could not defend, and many were obsolete biplanes. The Navy promised that a superior fleet would relieve Singapore, but it was estimated that it would take six months. There was only enough ammunition to fire once every six days if the relief took that long.
This force was attacked the first day of the war, and a landing was made the same day. English Army General Arthur Percival was informed to set up defensive lines, but thought it would be bad for morale. "It would be bad for morale when the Japanese start running all over the island," one of his staff officers replied.