A smouldering dispute between China and Japan over ownership of gas reserves in the East China Sea should be resolved by the time Hu Jintao, China’s president, visits Tokyo in spring, Beijing’s ambassador to Japan said on Friday.

Foreshadowing what could be the most significant breakthrough in Sino-Japanese relations in years, Cui Tian-kai, China’s ambassador, said: “We are making progress. Hopefully, we will arrive at a solution well before Hu’s visit.”