Since the tensions in the Korean peninsula started to intensify, there has been much discussion about what role Australia would play if North Korea attacked one of its allies. First there were questions about the ANZAUS treaty and whether Australia would be obligated to get involved if the war between the United States and North Korea switched from cold to hot. After North Korea fired a missile over Japan on Tuesday, talk shifted to whether and how Australia might come to Japan's aid in the event of an attack. But Australia already has a military presence in Japan, and has for the last six decades.

Following the outbreak of the Korean War in 1950 the United Nations established a multinational military force based in Tokyo called the United Nations Command, representing 16 nations that sent troops to the conflict. At the time it was under the command of US General Douglas MacArthur. When the command relocated to Seoul in 1957, it left behind the United Nations Command Rear (containing eight nations from the original) at Yokota Air Base, 40 kilometres west of Tokyo. The UNC rear is to be commanded by an Australian (with a Canadian second in command), currently Royal Australian Air Force Group Captain Michael Jansen.