HONG KONG — The tainted "gyoza" dumpling scare in Japan has caused the delay of President Hu Jintao's visit to Tokyo and, if not properly handled, could result in the unraveling of the dramatic improvement in bilateral relations achieved since October 2006, when Shinzo Abe broke the ice by visiting Beijing shortly after he became prime minister, followed by Premier Wen Jiabao's "ice melting" trip to Japan last spring.

Prime Minister Yasuo Fukuda added to the momentum when he visited Beijing and other cities in China last December and invited President Hu Jintao to visit Japan in the spring, "when the cherry blossoms are in full bloom."

Much hinges on this pending visit, which will be the first Chinese presidential visit to Japan in a decade and will fall on the 30th anniversary of the signing of the Sino-Japanese peace and friendship treaty in 1978.