The Touch Base Policy (Chinese: 抵壘政策) was implemented by the British Hong Kong Government in 1974, as an attempt to halt the influx of immigrants from Mainland China in the late 1960s and early 1970s.
Before 1949, people could move freely into and out of Hong Kong (then a British colony), and China (then Republic of China). In 1949, when the Government of the Republic of China retreated to Taiwan and the People's Republic of China was established on the mainland, Hong Kong experienced a large influx of refugees from Communist China. This population boom led to severe shortages in housing and social services in the territory.
In an attempt to halt this influx of immigrants, a Frontier Closed Area was established by the Hong Kong Government along the border with China in June 1951, and expanded to its current limit in 1962. Nonetheless the influx of immigrants continued, especially during the Cultural Revolution. In response the Hong Kong Government adopted the Touch Base Policy in November 1974, which allowed immigrants from Mainland China who reached the urban areas and met their relatives to register for a Hong Kong Identity Card. Those who were intercepted in the Closed Area would be repatriated back to the Mainland immediately.
The Touch Base Policy failed to halt the influx of immigrants, and was abolished by the Hong Kong Government on 24 October, 1980. Immigrants coming directly from the Mainland on or before 23 October 1980 were required to register for a Hong Kong Identity Card in a 3-day grace-period (24-26 of October 1980). Illegal immigrants arriving on or after 24 October 1980 were repatriated immediately, and it became compulsory for Hong Kong residents to carry their Identity Cards in public areas. That made the eligible immigrants who 'touched base' before the deadline rush to the Chinese Extension Section of the Immigration Department for identity registration.