Seiji Ozawa, Japan's most famous conductor, will not take part in a music festival in China later this week, organizers said, with media reporting that he was in hospital in Tokyo for tests.

The 75-year-old former Vienna State Opera musical director, who for many years was also conductor of the Boston Symphony Orchestra, was diagnosed with oesophogeal cancer in January 2010 and completed treatment later that year.

In January, he had endoscopic lower back surgery for chronic back pain and took a six-month break from conducting. But his comeback at the Saito Kinen Festival in the Japanese castle town of Matsumoto ran into trouble last week when he was diagnosed with dehydration and a light case of pneumonia, forcing him to cancel two of four performances.

He will not be taking part in performances in China, said a spokesperson at the Saito Kinen Festival, the organizer of the Chinese event.

She would not confirm media reports that Ozawa was in hospital for tests and unspecified treatment.

Ozawa was one of the first Asian classical musicians widely recognized abroad and has strived to revitalize the classical music scene in his native country by founding the Saito Kinen Festival.

Born the son of a dentist in 1935 in Shenyang, part of what was then Japanese-occupied China, Ozawa spent much of his early childhood in Beijing and has kept up connections with China since the late 1970s, when he was invited to work with a Chinese orchestra for a week.

Ozawa had been set to take part in four performances during the Chinese festival, which runs from Sept 1 to 11.

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