Indonesia–Malaysia confrontation

The Indonesia–Malaysia confrontation or Borneo confrontation (simply known as Konfrontasi in Indonesia, Malaysia and Singapore) was an armed conflict from 1963 to 1966 that stemmed from Indonesia's opposition to the creation of the state of Malaysia from the Federation of Malaya. After Indonesian president Sukarno was deposed in 1966, the dispute ended peacefully.

The creation of Malaysia was a merger of the Federation of Malaya (now Peninsular Malaysia), Singapore and the British crown colonies of North Borneo and Sarawak (collectively known as British Borneo, now East Malaysia) in September 1963. Vital precursors to the conflict included Indonesia's policy of confrontation against Dutch New Guinea from March–August 1962 and the Indonesia-backed Brunei revolt in December 1962. Malaysia had direct military support from the United Kingdom, Australia, and New Zealand. Indonesia had indirect support from the USSR and China, thus making it an episode of the Cold War in Asia.

The conflict was an undeclared war with most of the action occurring in the border area between Indonesia and East Malaysia on the island of Borneo (known as Kalimantan in Indonesia). However Indonesia also conducted lower intensity covert actions on Malay peninsula and Singapore. The conflict was characterised by restrained and isolated ground combat, set within tactics of low-level brinkmanship. Combat was usually conducted by company- or platoon-sized operations on either side of the border. Indonesia's campaign of infiltrations into Borneo sought to exploit the ethnic and religious diversity in Sabah and Sarawak compared to that of Malaya and Singapore, with the intent of unravelling the proposed state of Malaysia.

During Konfrontasi from 1963 to 1966, there was fighting between the Indonesian, Malaysian and Commonwealth forces along the long land border that Malaysia shared with Indonesia in East Malaysia. Many soldiers spent months patrolling the border, including Singaporean and Australian soldiers in Sarawak.

The jungle terrain of Borneo and the lack of roads straddling the Malaysia–Indonesia border forced both Indonesian and Commonwealth forces to conduct long foot patrols. Both sides relied on light infantry operations and air transport, although Commonwealth forces enjoyed the advantage of better helicopter deployment and resupply to forward operating bases. Rivers were also used as a method of transport and infiltration. Although combat operations were primarily conducted by ground forces, airborne forces played a vital support role and naval forces ensured the security of the sea flanks. The British provided most of the defensive effort, although Malaysian forces steadily increased their contributions, and there were periodic contributions from Australian and New Zealand forces within the combined Far East Strategic Reserve stationed then in West Malaysia and Singapore.

Initially, Indonesian attacks on East Malaysia relied heavily on local volunteers trained by the Indonesian Army. Over time, infiltration forces became more organised with the inclusion of a more substantial component of Indonesian forces. To deter and disrupt Indonesia's growing campaign of infiltrations, the British responded in 1964 by launching their own covert operations into Indonesian Kalimantan under the code name Operation Claret. Coinciding with Sukarno announcing a 'year of dangerous living' and the 1964 race riots in Singapore, Indonesia launched an expanded campaign of operations into West Malaysia on 17 August 1964, albeit without military success. A build-up of Indonesian forces on the Kalimantan border in December 1964 saw the UK commit significant forces from the UK-based Army Strategic Command. Australia and New Zealand deployed roulement combat forces from West Malaysia to Borneo in 1965–66. The intensity of the conflict began to subside following the coup d'état of October 1965 and Sukarno's loss of power to General Suharto. A round of serious peace negotiations between the two sides began in May 1966, and a final peace agreement was signed on 11 August 1966 with Indonesia formally recognising Malaysia.