Former defense minister Yuriko Koike, a candidate planning to run in the Tokyo Governor election, attends a joint news conference with other potential candidates at the Japan National Press Club in Tokyo, Japan July 13, 2016. REUTERS/Issei Kato/Files

Former defense minister Yuriko Koike, a candidate planning to run in the Tokyo Governor election, attends a joint news conference with other potential candidates at the Japan National Press Club in Tokyo, Japan July 13, 2016. REUTERS/Issei Kato/Files

Former defense minister Yuriko Koike, a candidate planning to run in the Tokyo Governor election, attends a joint news conference with other potential candidates at the Japan National Press Club in Tokyo, Japan July 13, 2016. REUTERS/Issei Kato/Files

July 31, 2016 11:12 AM (UTC+8)