HONG KONG — Forty-five years ago, China and India — the world's two most populous countries — were at each other's throats, fighting a bloody war along their common border. Ten years ago, when India conducted underground nuclear tests, its defense minister said the country needed to develop nuclear weapons to deter a possible China threat.

This month, Indian Prime Minister Manmohan Singh visited China and, on the surface at least, all was sweetness and light. It was the first visit by an Indian prime minister in five years and served to improve the atmospherics of a relationship that had been marked by an absence of trust for too long.

No major issues were resolved. The boundary dispute between the two countries remains intractable and it emerged at this visit that China and India have rather different approaches to the issue.