Yuichi Yoshikawa visits the south entrance of the Diet building every June 15 to offer flowers in memory of a female college student who died there in a clash between police forces and anti-Japan-U.S. security treaty demonstrators on the day 50 years ago.

Hundreds of thousands of protesters surrounded the building every day to express their opposition to the bilateral treaty "as we still had vivid memories of World War II, which had ended only 15 years (earlier), and believed the treaty would lead to another war," said Yoshikawa, 79, a veteran peace campaigner.

"When only a few people started a march with a flag, other people joined at their own initiative to make it hundreds of demonstrators at last, with antiwar sentiment stirred also by the outbreak of the Korean War and the launch of the Self-Defense Forces in the 1950s," he said.