II. The phase of deterioration

In the late 1950s, border disputes and the Tibet issue resulted in a war between the two countries and bilateral ties entered an "ice age."

On October 18, 1958, Indian government put forward an official claim to the Aksai Chin region, claiming it was "part of Ladakh District." In November, China replied in a note refuting India's claim.

In March 1959, the Dalai Lama fled to India in the wake of the failed rebellion in Tibet. In August, the first military conflict between China and India, the Langjiu Incident took place.

In June 1962, the Agreement between the People's Republic of China and the Republic of India on Trade and Intercourse between Tibet Region of China and India expired. Diplomatic relations were lowered to the level of Charge d'affaires. In October, the Sino-Indian Border Conflict broke out.

III. The phase of rehabilitation

After a long period of confrontation, the two sides both realized the importance of bilateral ties. In the middle and late 1970s, leaders on both sides made great efforts to normalize diplomatic relations.

1. The normalization of Sino-Indian diplomatic relations

In July 1976, China and India restored ambassadorial relations after negotiations between the two governments. Kocheril Raman Narayanan and Chen Zhaoyuan were appointed ambassadors.

In February 1979, Indian External Affairs Minister, Atal Bihari Vajpayee, visited China. China put forward a package of proposals on mutual understanding and concessions on border issues, displaying China's active willingness to solve the issues.

In June 1981, Huang Hua, vice premier and foreign minister, paid a visit to India. It was the first visit to India by a Chinese leader since 1960. During the visit, the two governments agreed to continue negotiations on boundary and other issues.

In December 1981, the two countries held the first boundary negotiations in Beijing.

In December 1986, India upgraded Arunachal to Arunachal Pradesh, drawing a strong protest from China. China refused to acknowledge the existence of so-called Arunachal Pradesh.

In November 1987, at the eighth boundary negotiation India moderated its hard-nosed stance on border issues.

In December 1988, Indian Prime Minister Rajiv Gandhi visited China at the invitation of Chinese Premier Li Peng. The resumption of dialogue between the leaders of the two countries after being suspended for 28 years marked the normalization of bilateral ties.