Byakuren's Republic of Thailand, more commonly known as Thailand is a nation in South East Asia.
Thailand was mostly left alone and got annoyed with the fight over British India and French Indochina. The French and British in Indochina and India respectively were constantly arguing with one another and the Thais just wanted them to be quiet. Fortunately, the Thais got their wish when the Empire of Gensokyo invaded French Indochina in 1941. The French were kicked out of Indochina and most French were killed as well. Unfortunately, Thailand itself was invaded by Gensokyo in 1942. The Thais quickly agreed to help the Japanese, and went on a join invasion of British Malaysia and the Grand Dutch Coffee Shop Company in the Dutch East Indies, which resulted an annexation of both areas to Thailand after conquest. Soon the Dutch Coffee Shop went bankrupt and went back to the Netherlands, and the British were kicked out fully, or escaped to Australia. Afterwards, Thailand was finally glad to no longer deal with the annoying French-British argument and peace in South-East Asia was finally achieved.
That is, until Australia proved to pose a threat. As such, Thailand shut down it's Thai-Australian borders and the Greater East Asia Treaty Organisation is on full alert about the threats Australia pose. For right now, temporary peace is enjoyed, though the Cold War could change it's course of direction.