In December 1941, the Empire of Japan began its assault on British Borneo; by January 1942 its armies had begun to attack those parts of the island which were part of the Dutch East Indies. This was followed by attacks on Sumatra and Java in February. Ultimately, the Dutch colonial government capitulated on 8 March 1942, though pockets of resistance lasted for several months. In the succeeding months, the Japanese government closed the banks, seized assets and currency, and assumed control of the Indies' economy.