Asia Pacific 1941: Franco-Thai War
Thailand saw the French capitulation to Japan as weakness, seizing the opportunity to regain lost territories by invading French Indochina. The Japanese quickly put a stop to this war, but supported Thai claims at the ensuing peace treaty. With its focus now on the south, Japan signed a neutrality pact with the Soviet Union.
Treaty ports were towns opened to foreign trade by unequal treaties in China. Foreigners operating within treaty ports enjoyed extraterritoriality, being subject to their home country's laws. Unlike concessions such as Hong Kong, these territories were not directly leased by the foreign powers and did not have sizable foreign garrisons.
Treaty ports are not shown in the maps after the 1911 Chinese Revolution in order to give a clearer picture of the chaos in China itself and as by that point their numbers had stabilized. After the revolution, some of the smaller ports were phased out while the others became less important as the situation in China meant that only the concessions could provide foreigners with security. Most, however, still continued on into the 1940s when the Japanese entry into World War II and foreign agreements with China brought them to an end.
See this map for treaty ports in 1907, when the system was at its peak.
By the terms of the Treaty of Tientsin (1858), foreign vessels including warships had the right to free navigation on the Yangtze River. In practical terms, this right extended only as far as Yichang until 1900, when advances in steam navigation allowed access as far inland as Chongqing.
27 Sep 1940 Tripartite Pact▲
Joachim von Ribbentrop of Nazi Germany, Galeazzo Ciano of the Kingdom of Italy, and Saburō Kurusu of the Empire of Japan signed the Tripartite Pact in Berlin, capital of Germany. The 10 year Pact recognized the right of Germany and Italy to establish a new order in Europe while Japan did so in Greater East Asia; it also compelled the contracting Powers to come to the aid of any one of them should they be attacked by a Power not presently involved in either World War II in Europe or the Sino-Japanese War (implicitly making it a defensive pact against the United States and the Soviet Union).
18 Oct 1940 British reopening of Burma Road▲
Following the Japanese occupation of northern French Indochina and the continuation of Japanese offensives in China, the United Kingdom ended its conditional three month closure of the Burma Road, allowing supplies to reach Nationalist China again.
5 Jan–9 May 1941 Franco-Thai War▲
Following a number of border skirmishes along the disputed Mekong frontier, war erupted between the Kingdom of Thailand and Vichy-controlled French Indochina. While the superior Royal Thai Air Force bombed cities in Laos and Cambodia, the Thai army overran French border defenses. The war was brought to an end by a Japanese mediated ceasefire, after which French Indochina was forced to cede most of the disputed territory to Thailand.
31 Jan 1941 Franco-Thai armistice▲
Following a Japanese-sponsored "Conference for the Cessation of Hostilities", the Vichy government of France signed a ceasefire with the Kingdom of Thailand aboard the Japanese cruiser Natori. A formal peace treaty was signed in Tokyo on 9 May, whereby France agreed to cede Battambang, Pailin, Siem Reap, Banteay Meanchay, Oddar Meanchey, Preah Vihear, and Xaignabouli to Thailand.
13 Apr 1941 Soviet-Japanese Neutrality Pact▲
The Empire of Japan signed a non-aggression pact with the Soviet Union, safe-guarding both nations against a war on multiple fronts. The treaty was signed in Moscow by Foreign Minister Yosuke Matsuoka and Ambassador Yoshitsugu Tatekawa for Japan and Foreign Minister Vyacheslav Mikhailovich Molotov for the Soviet Union. At the same time, the Soviet Union pledged to respect the territorial integrity and inviolability of Manchukuo, while Japan did the same for the Mongolian People's Republic.