History of Singapore
During World War 2, Singapore was conquered and occupied by the Japanese Empire from 1942 to 1945. When the war ended, Singapore reverted to British control, with increasing levels of self-government being granted, culminating in Singapore's merger with the Federation of Malaya to form Malaysia in 1963. However, social unrest and disputes between Singapore's ruling People's Action Party and Malaysia's Alliance Party resulted in Singapore's expulsion from Malaysia. Singapore became an independent republic on 9 August 1965.
Japan–Singapore relations
Japan and Singapore had little interaction for decades following the occupation. In 1959, a request for reparations was submitted to the Japanese government, but Japan refused them on the grounds that Singapore was still a crown colony of Britain, and they had already paid reparations to Britain in 1951. Singapore existed as a crown colony of the United Kingdom until 1963, during which they merged to become a state of Malaysia. However, following major political disagreements and racial disputes, the Malaysian government unanimously voted to expel Singapore from the union, resulting in Singapore's complete independence on August 9, 1965.