evidence: It is isolated not only geographically, but also diplomatically. China enforced a long-held claim to Tibet in 1950, and it was subsequently incorporated into Chinese territory. [...] China believes Tibet to be an important reservoir of natural resources. It is the prime source of Asia's major rivers, and harbours extensive forest and minerals. [...] Around half the landmass the Tibetans consider to be Tibet has been subsumed into other Chinese provinces, and in 1965 the Chinese government named the rest the Tibetan Autonomous Region (TAR).