When did the Japanese decide to invade Malaya in WWII?

Plans for a Japanese invasion of the Malayan peninsula were well under way long before the Australian troops docked in Singapore. In fact only a couple of months after the formation of the 2/20 Battalion AIF, the Japanese were already checking out their target.

On 10 September 1940, almost 1 year and 3 months before the invasion, Colonel T Tanikawa, the planning chief of Japan’s Imperial Army Tokyo headquarters arrived in Singapore. This high ranking Army man was accompanied by Major Kunitake who subsequently became a staff officer of the 25th Army under General Yamashita, the army which eventually attacked Malaya and Singapore.

Colonel Tanikawa and Major Kunitake wanted to travel along the east and west coasts of Malaya to investigate the condition of the coast. Accompanied by Press Attaché Mamoru Shinozaki, they toured Singapore itself, along the coast road, visiting Changi, Katong, Siglat and Pasir Panjang. They drove round the Tengah Air base, then under construction, they drove along the Bukit Timah Road to Johore Bahru then Koto Tinggi, Mersing and Endau and onto Malacca.

On 13 September they returned to Singapore to the home of former Army Captain Yamakawa, a veteran from the Russo-Japanese war, who had settled in Singapore. The men studied a map of the country and Tanikawa declared ‘It is impossible to attack Singapore from the sea, that is, from the east, south or west. Attack is possible only from the Johore Strait north of Singapore.’
This was confirmed by Tsuji when he wrote’ The south and east seafronts of Singapore are strongly defended, there are no fortification of strength on the Johore side. The RAF is not as strong as the newspapers say. The number of troops at Kedah is increasing.’

The next day the two officers Tanikawa and Kunitake returned to Japan and passed on their information to Lieutenant-Colonel Tsuji, the chief planner of Yamashita’s army.

Following this meeting, Shinozaki was charged by the Special Branch of the Singapore Police with ‘collecting information which might be useful to a foreign power.’ But there were plenty of others who were still  collecting intelligence for the Japanese, many of the local people who were ‘fifth columnists’,  and other soldiers like Captain Hunitake Terito who travelled incognito through Malaya and Singapore from January to March 1941 gathering more information.

Shinozaki was jailed at Changi where he remained until the Japanese eventually took over Singapore when he became a city administrator in charge of schools. In his book he remarked that ‘now the battle of the soldiers was over. The people’s pain and suffering was about to begin – pillage, violence, slaughter.’ How right he was.

References: Mamoru Shinozaki,  Syonan – my story… the Japanese occupation of Singapore, Asia Pacific Press, River Valley Road, Singapore, 1975

Sqd Ldr Hugh Dolan and Alex McDermott, Battle For Australia, Part 1 The Fall of Singapore, 2013, Z Beach True Comics and Australian Teachers of Media,