By Jonathan Head
BBC News, Tokyo
A senior Chinese official is arriving in Japan on Tuesday for a week-long visit which could help repair damaged relations between the two countries.
Wu Yi may not have been the person Tokyo was hoping to see
Vice-Premier Wu Yi will spend much of her time at the World Expo in the Japanese city of Nagoya, discussing economic ties with Japan.
But she may meet Prime Minister Junichiro Koizumi later this week.
Last month, there were violent anti-Japanese demonstrations in several cities across China.
They were sparked by allegations Japan was glossing over its abuses during World War II.
Vice-Premier Wu Yi is the highest-ranking woman in the Chinese Communist Party, an admired politician credited with sorting out China's entry into the World Trade Organisation and the crisis over the Sars virus two years ago.
She has the right credentials for helping heal the rift with Japan. But she is not the person Japan had hoped to see right now.
Prime Minister Junichiro Koizumi had actually invited her boss, Premier Wen Jiabao, to the Aichi Expo.
That China has chosen to send someone less senior is a subtle sign of continuing displeasure in Beijing over Japan's treatment of its history and its aspiration to become a permanent member of the UN Security Council.
The two countries are also at odds over access to oil and gas reserves.
Vice-Premier Wu has so far only scheduled economic talks in Japan. There is no confirmation yet of a meeting with any senior Japanese politicians, although officials say she may see Prime Minister Koizumi later this week.
It appears the Chinese are playing a slow game, making Japan wait for an improvement in relations, although neither country can afford to see their trade - now valued at around $170bn a year - put at risk by a repetition of last months anti-Japanese protests.