From Japan Runs Wild, 1942–1943, by Peter Harmsen (War in the Far East, Book 2; Casemate, 2020), Kindle pp. 22-24, 40:
The first troops which the Japanese encountered when disembarking on the Malay coastline were Indians, and Indian units remained their main opponent throughout the campaign. Britain used one part of its empire to defend another. Out of 31 Commonwealth battalions deployed on the Malay Peninsula, 18 were Indian, six were British, six were Australian, and one was Malay. A large number of Indian troops had originally been earmarked for the Middle East and had undergone training in Australia, specializing in tactics suitable for desert warfare. Now they were in the jungle. “One could argue that the Commonwealth troops in Malaya failed to unlearn the lessons of desert warfare in tropical conditions,” Indian military historian Kaushik Roy writes, “and failed to adopt the required tactical techniques for fighting effectively in the different ecological landscape.”
The poor preparation of the Commonwealth troops made the preparations carried out by the Japanese seem all the more impressive. As a matter of fact, the Japanese campaign in Malaya was a rush job, planned in less than a year by a small group of dedicated officers operating on a minimal budget, seeking information from whoever in the Japanese Empire might be a good source. An old sea captain who had spent many years plying routes in the areas Japan planned to invade provided details about weather patterns and coastal conditions. The Ishihara Mining Company had useful information about the geography of the Malay Peninsula. Professors at Taiwan University filled the group in on hygiene in the tropics and measures against malaria.
The Japanese, whose main experience with war had been on the Mongolian steppe and the rice fields of China, were no more used to jungle warfare than their Western counterparts, but they went into battle better prepared because of the questions that the planners asked, and found answers to. “What alterations had to be made in the organization of troops and the type of weapons and equipment used on the Siberian and Manchurian battlefields at twenty degrees below zero to meet requirements for fighting in the dense jungles of the tropics?” asked the planners, led by the capable but brutal officer Tsuji Masanobu. “How should tactics and strategy used against the Soviet Union be revised for action against British and American armies, and what comparisons could be made between the tactics, equipment and organization of Soviet, British, and American troops?”
The preparations paid off. The Japanese soldiers landing in Malaya were equipped for quick, decisive movements through terrain where modern roads were only sparse. They had light tanks, light trucks, and first and foremost bicycles. An Australian staff officer, C. B. Dawkins, concluded that the Japanese had, in fact, understood what the Westerners had not: “Jungle, forest and rubber areas are par excellence infantry country—every move is screened from air and ground observations, the value of fire of weapons of all natures is very limited, and troops on the offensive can close to within assaulting distance unmolested.”
By Christmas, Lieutenant General Arthur Ernest Percival, the overall commander of Commonwealth forces in Malaya, had to revise many previously held views of the Japanese foes, as he explained later: “It was now clear that we were faced by an enemy who had made a special study of bush warfare on a grand scale and whose troops had been specially trained in those tactics. He relied in the main on outflanking movements and infiltration by small parties into and behind our lines… his infantry had displayed an ability to cross obstacles—rivers, swamps, jungles, etc.—more rapidly than had previously been thought possible.”
Faced with a terrifying foe, the Commonwealth defenders went from underestimating the Japanese foes’ quality to overestimating their quantity. “A British soldier is equal to ten Japanese, but unfortunately there are eleven Japanese,” an injured Tommy told American correspondent Cecil Brown. The British Army in Malaya could not believe it was being beaten by the Japanese, and its members had to conjure up superior numbers to explain what happened to them. In fact, there were about twice as many British-led soldiers as there were Japanese. In Malaya as in all other major land campaigns that the Japanese waged early in the war, they invariably fielded numerically inferior troops, which nevertheless excelled in all other parameters.
National differences came out more clearly in the harsh jungle. The stiff pecking orders of the British military were maintained even in the primitive conditions, whereas the flat hierarchies of the Australians appeared to some observers more suited for the new strange environment. “The Australian Army is undoubtedly the world’s most democratic, and the troops in Malaya prove it,” wrote American correspondent F. Tillman Durdin, reporting how the salute resembled a “Hi, there” gesture. “An Australian officer can command his men only if he proves himself as good a man as any of his unit.”