Aussie Soldier in Kalimantan
The Indonesian–Malaysian confrontation or Borneo confrontation (also known by its Indonesian/Malay name, Konfrontasi) was a violent conflict from 1963–66 that stemmed from Indonesia's opposition to the creation of Malaysia. The creation of Malaysia was the amalgamation of the Federation of Malaya (now West Malaysia), Singapore and the crown colony/British protectorates of North Borneo and Sarawak (collectively known as British Borneo, now East Malaysia) in September 1963.[ Important precursors to the conflict included Indonesia's policy of confrontation against Netherlands New Guinea from March–August 1962 and the Brunei Revolt in December 1962.
The confrontation 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). 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 unraveling the proposed state of Malaysia.
The challenging jungle terrain of Borneo and 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, aerial 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.
Initial Indonesian attacks into East Malaysia relied heavily on local volunteers trained by the Indonesian Army. With the passage of time infiltration forces became more organised with the inclusion of a larger 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 and 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 events of the 30 September Movement and Suharto's rise to power. A new round of peace negotiations between Indonesia and Malaysia began in May 1966 and a final peace agreement was signed on 11 August 1966 with Indonesia formally recognising Malaysia. Wikipedia