The historical Japanese advance through Malaya depended on access to bases and airfields in French Indochina. In this scenario those positions must first be captured from an Allied territory that can receive British and French reinforcement. British Indian, Australian, and other troops also face fewer diversions in Africa, Syria, Madagascar, and the Middle East, placing better formations in the Far East. Japan would therefore struggle to establish the springboard needed to reach Singapore at all.
Chapter · 2:24:18-2:26:43
Japan loses the Indochina springboard to Singapore
Without secure bases in French Indochina, Japan cannot mount the historical drive through Malaya under the same conditions.