Japan's relations with China are likely to remain difficult due to rising nationalism in both countries and periodic tension-causing incidents, a longtime Asia affairs expert predicted Tuesday.

Robert Scalapino, a professor emeritus at the University of California, Berkeley, said, "Directly or indirectly, a future China threat forms a part of Japan's strategic planning, and renders support to a continuance of the strategic alliance with the U.S. even as Tokyo evidences a desire to move from patron-client relations to partnership.

"With nationalism rising in both China and Japan, the relations between these two nations are likely to be difficult in the years ahead, with periodic incidents causing tension," he said on the first day of a three-day symposium on Northeast Asia in Kanazawa, Ishikawa Prefecture.

Scalapino said the U.S. will continue to play a key role.

"The U.S. commitment is almost certain to help foster an evolutionary approach to both issues, avoiding conflict or abrupt change through political upheaval," he said. "Support will be required from others, especially China — and China's capacity to accept the status quo with regard to Taiwan indefinitely is clearly uncertain."

Officials and scholars from Japan, the U.S., China, Russia and six other countries are attending the symposium, the eighth in a series that began in 1995. North Korea was also invited to the forum but did not attend.