Thailand officially joined the war in January 1942. Main article: Thailand in World War II HTMS Matchanu and HTMS Wirun, Kobe Port, 1938ĭuring World War II, Siam allied with Japan after Japan invaded Siam on 8 December 1941. Within a month of the engagement, the French and the Thais had negotiated a peace that ended the war. The Japanese intervened diplomatically and mediated a ceasefire. The battle was a tactical victory by the French Navy over the Thai Navy although the strategic result is disputed. During the post-action investigations, the Thai Navy claimed, based on statements by Thai sailors and the fisherman around Ko Chang and merchantmen in Saigon, that heavy damage was seen to have been caused to the French ship Lamotte-Picquet and her squadron. The Thai transport HTMS Chang arrived at Ko Chang shortly after the French departed and took the Thonburi in tow, before purposefully running her aground in Laem Ngop. The HTMS Thonburi was heavily damaged and grounded on a sand bar at the mouth of the Chanthaburi River, with about 20 dead. The Battle of Ko Chang took place on 17 January 1941 during the Franco-Thai War in which a flotilla of French warships attacked a smaller force of Thai vessels, including a coastal defence ship. The force was commanded by Major General Phraya Bhijai Janriddhi and was sent to France. By early-1918, 1,284 men were selected from thousands of volunteers. Siamese sailors were part of a volunteer expeditionary force, consisting of medical, motor transport, and aviation detachments. He also used the war as a means to promote the concept of a Siamese nation. The war did, however, provide an opportunity for King Rama VI to strengthen his country's position in the international arena. The First World War had no direct impact on Siam due to its distance from the fighting. Main article: Siam in World War I The Siamese Expeditionary Force, Paris, 1919

World of warships operation narai?