From the 20 th century onwards By the end of the 19 th century, Britain and France had succeeded in dividing the mainland of Southeast Asia. Thailand barely survived, skillfully maneuvering between the British and the French to keep its independence but being economically dependent on and dominated by both European powers. By the 20 th century, the borders between the mainland states had been firmed up: between Thailand and Laos, Thailand and Cambodia, Thailand and Burma, Burma and Laos, and Burma and China. Vietnam’s overland border with China had been settled by the 15th century when the last Ming attempt to invade Vietnam failed. It was more or less the same border that was drawn up between China and Vietnam in the 10 th century. As regards the sea borders, the Dutch drew borders between their Netherlands East Indies and the Spanish Philippines. The Americans later displaced the Spanish, taking over the Philippines in 1898 and linked it even more strongly with America on the other side of the Pacific. This was also the time when Japan grew into an economic, naval and colonial power by learning from the West. Japan’s take-over of Taiwan in 1895 was the opening of its thrust into the region. Unlike China that had overland access to the region, Taiwan was the key entry point for Japan to invade Southeast Asia from the north. The climax of the shaping of Southeast Asia was when the Japanese invaded the region in 1941. The invasion was the first obvious recognition by Japan that here was a region which was separate from China and could be connected with India. At the peak of Japan’s power in Southeast Asia in 1942, every coast of the South China Sea was under Japanese control, effectively turning the South China Sea into a Japanese lake. This reminds us of the centrality of the South China Sea in the definition of Southeast Asia. However, it is also important to recognise China’s historic position with regards to that Sea because its northern coast was China’s southern border from the Han dynasty since the 1st century BC. The South China Sea is not a Southeast Asian or Chinese sea. Geographically and historically, it has always been a sea shared between the Malay archipelago, the mainland of Southeast Asia and China. It was the response of the Allied Powers to the Japanese invasion that firmed up the conceptualisation of Southeast Asia as a region. The British established the South East Asia Command (without the Philippines which was then under the US Far Eastern Command) – a strategic naming that brought the term “Southeast Asia” to life. The period between 1941 and 1945 were the critical years when the shaping of Southeast Asia came to a head. Finally, Southeast Asia became real in the eyes of more and more people. From the 1950s onwards, literature on Southeast Asia flourished with the publication of history and geography books about the region. Numerous universities in the world took up the challenge of defining Southeast Asia – its long history, how it became a region, why it deserved to be recognised as a region with its own identity and character. Prof. Wang Gungwu delivering the ISEAS 50th Anniversary Lecture 4 — ISSUE 5/2018 ISEAS-Yusof Ishak Institute controlled the Malay peninsula and the Dutch advanced deeper into Indonesia. They set up colonial states that had sophisticated bureaucratic structures, and introduced their laws and systems of governance as well as new ways of thinking about how rulers should behave and how people should be ruled. They divided the territories among themselves and marked out borders that did not relate to the earlier borders, especially in the Malay archipelago. By doing so, they created a new and different set of diversity and fragmentation for the region.