Japanese foreign policy toward Southeast Asia, the diverse region stretching from South Asia to the islands in the South Pacific Ocean, was in part defined by Japan's rapid rise in the 1980s as the dominant economic power in Asia. The decline in East-West and Sino-Soviet tensions during the 1980s suggested that economic rather than military power would determine regional leadership. During the decade, Japan displaced the United States as the largest provider of new business investment and economic aid in the region, although the United States market remained a major source of Asia-Pacific dynamism. Following the rise in value of the yen relative to the US dollar in the late-1980s (after the Plaza Accord), Japan's role as a capital and technology exporter and as an increasingly significant importer of Asian manufactured goods made it the core economy of the Asia-Pacific region. Japan remains the largest donor of economic aid to the region. 1950s From the mid-1950s to the late 1960s, Japan's relations with the rest of Asia were concerned mainly with promoting its far-flung, multiplying economic interests in the region through trade, technical assistance, and aid. Its main problems were the economic weakness and political instability of its trading partners and the growing apprehension of Asian leaders over Japan's "overpresence" in their region. Japan began to normalize relations with its neighbors during the 1950s after a series of intermittent negotiations, which led to the payment of war reparations to Burma (now Myanmar), Indonesia, the Philippines, and the Republic of Vietnam (South Vietnam). Thailand's reparations claims were not settled until 1963. Japan's reintegration into the Asian scene was also facilitated by its having joined the Colombo Plan for Cooperative Economic and Social Development in Asia and the Pacific in December 1954 and by its attendance at the April 1955 Afro-Asian Conference in Bandung, Indonesia. In the late 1950s, Japan made a limited beginning in its aid program. In 1958 it extended the equivalent of US$50 million in credits to India, the first Japanese loan of its kind in post-World War II years. As in subsequent cases involving India, as well as Sri Lanka, Malaysia, Taiwan, Pakistan, and South Korea, these credits were rigidly bound to projects that promoted plant and equipment purchases from Japan. In 1960 Japan officially established the Institute of Asian Economic Affairs (renamed the Institute of Developing Economies in 1969) as the principal training center for its specialists