News spread of the Japanese invasion of North Vietnam and their readiness to invade Europe’s colonies in South East Asia by the end of 1940. In July 1941, the Japanese triumphed over Cochin-China in South Vietnam, which was located only 500 km from Kota Bharu, Kelantan and 1,000 km from Singapore. The Japanese arrived at Pantai Pak Amat in Kota Bharu on 7 December 1941 in the morning, during which time the students in Malay College, including Tun Razak, were sitting for their final examination. The examination was cancelled and students were asked to return to their hometowns as the residential buildings would be used as a field hospital. However, Tun Razak refused. Together with Hamdan Tahir, he worked at the hospital as a member of Perkhidmatan Perubatan Tambahan. Tun Razak was impressed by the courage and bravery of Malay fighters such as Leftenan Adnan who fought for their beloved nation to the last breath. The British Defense could not withstand the Japanese onslaught in Malaya and Singapore. When British defeat seemed imminent, Tun Razak and some of his friends returned to their hometowns via the midnight freight train. A few days later, just as Tun Razak arrived in Bentong, the Japanese conquered Kuala Lumpur and were moving towards the south.
The left-leaning Kesatuan Melayu Muda (KMM) led by Ibrahim Yaacob was formed in 1938. It consisted of graduates of the Sultan Idris Training College (SITC) who later joined up with Malay graduates from other institutions such as MCKK. Their aim was to achieve Independence for Malaya through a political union with Indonesia, forming Melayu Raya or Indonesia Raya. During the Japanese Occupation, KMM sought the patronage of the Japanese, believing that the Japanese would grant Malaya Independence. However, the Japanese disbanded KMM in 1942, out of fear of a political uprising against them.
On 8th August, an Indonesian delegation headed by Sukarno and Mohammad Hatta had talks on Indonesian independence in Saigon with the Japanese. On the way back, they stopped in Taping to meet with Ibrahim Yaacob and other KMM officials. Ibrahim told Sukarno of the idea of "Melayu Raya" (or Indonesia Raya). Sukarno was said to have been enthusiastic, but Hatta less so. (Source: Red Star Over Malaya, Cheah Boon Kheng, NUS Press)
After the Japanese surrendered, the British sought to regain their control over Malaya. Sir Harold Macmichael met with the Malayan Sultans and managed to obtain their agreement to the MacMichael Treaty. The treaty proposed a Malayan Union (comprising Malay states, Malacca and Penang) to replace British Malaya. There would be equal citizenship rights and the power of the Malay Sultans would be heavily curtailed, confined to religious affairs. The Macmichael Treaty resulted in the awakening of Malay political consciousness. Datuk Onn Jaafar formed a national movement to oppose the Malayan Union.
Indonesia proclaims Independence on 17th August 1945. It caught the KRIS members by surprise as they had not been consulted nor informed. KRIS instructed its members to take over Japanese military installations and buildings, but without Japanese support, efforts to oppose the British collapsed.
At the time of the Japanese surrender, the Malayan People's Anti-Japanese Army (MPAJA), a resistance offshoot of the Malayan Communist Party, emerged as the strongest political (and armed) group in Malaya. There were between 3,000 to 7,000 members of the MPAJA. (Source: Red Star Over Malaya, Cheah Boon Kheng, NUS Press).
British forces return to Malaya, re-establishing its occupation, and the British Administration is set up.
The British, under its Socialist post-war government, proposed the establishment of the Malayan Union to centralise the administration of the Straits Settlements (Penang, Singapore, Melaka), Federated Malay State (Perak, Selangor, Negeri Sembilan, Pahang) and Unfederated Malay States (Johor, Kedah, Perlis, Terengganu, Kelantan).
Sir Harold Macmichael arrived in Malaya on 11th October 1945 tasked to secure the Sultans' agreement to the Malayan Union. On 20th October, the Sultan of Johor inked his agreement, and by 21st December 1945, all nine Sultans had agreed to the Malayan Union, despite the loss of their sovereignty.
In late December 1945, the first demonstration against the Malayan Union took place in Kota Bharu, Kelantan, where over an estimated 10,000 people greeted Sir Harold Macmichael upon his arrival to the state with placards denouncing the Malayan Union.