It is the diplomatic acknowledgement of China's position that there is only one Chinese government. Under the policy, the US recognises and has formal ties with China rather than the island of Taiwan, which China sees as a breakaway province to be reunified with the mainland one day.
The One China policy is a key cornerstone of Sino-US relations. It is also a fundamental bedrock of Chinese policy-making and diplomacy. However, it is distinct from the One China principle, whereby China insists Taiwan is an inalienable part of one China to be reunified one day.
The US policy is not an endorsement of Beijing's position and indeed as part of the policy, Washington maintains a "robust unofficial" relationship with Taiwan, including continued arms sales to the island so that it can defend itself.
Although Taiwan's government claims it is an independent country officially called the "Republic of China", any country that wants diplomatic relations with mainland China must break official ties with Taipei.
This has resulted in Taiwan's diplomatic isolation from the international community.
