Border dispute an obstacle to building trust between China and India

"Shall we keep on quarrelling like this? We must become friends again."

The then Indian chargé d'affaires Brajesh Mishra couldn't believe his ears at Chairman Mao Zedong's cue as they shook hands at a May Day parade on the Tiananmen rostrum in 1970.

The wounds of the 1962 border war, in which India suffered a humiliating defeat, were still raw. Pointedly, Mishra was placed at the end of the line-up of diplomats arranged in order of precedence to meet Mao - after the British chargé d'affaires - making the gesture all the more dramatic.

Mishra immediately saw the opening Mao was creating for ties to resume, and was relieved it meshed with his own brief. Before he left for Beijing, then prime minister Indira Gandhi had laid it out for him in one sentence: "I am in a box so far as relations with China are concerned, and I want us to get out of that box."

Despite this common yearning for détente, China and India would soon drift further apart - this time over the Bangladesh liberation war in 1971. While India backed the Bengali freedom fighters, Beijing threw its lot behind its "all-weather friend" Islamabad - a relationship that would dog Sino-Indian relations for decades.

It wasn't until the 1990s that China and India would finally start a structured process of normalising ties. Economic relations have since gone from strength to strength, with China now India's largest trading partner. But as the recent three-week Himalayan stand-off brought home, the undercurrent of animosity still runs deep, and the possibility of unfriending each other all over again is never far away.