First of a six-part series looking back on 50 years of Japanese-U.S. relations since the 1951 signing of the San Francisco Peace Treaty and the bilateral security treaty. By JUNKO TAKAHASHI Staff writer Nobuo Matsunaga was a young diplomat in Paris when Japan signed the San Francisco Peace Treaty, which officially ended its state of war with the United States and 47 other countries on Sept. 8, 1951.

The treaty, and a subsequent security alliance with the U.S., set the direction for postwar diplomacy. Now that the 50th anniversary is approaching, experts say Japan should take greater diplomatic initiatives on its own, instead of mainly following the lead of the U.S.

"All the Japanese in Paris heard with great joy and excitement the news that we finally had regained our sovereignty on that day," recalled Matsunaga, who climbed to the top rung of the diplomatic corps as vice foreign minister and ambassador to the U.S.