HANOI, Vietnam (AP) — Japanese Crown Prince Akishino, the younger brother of Emperor Naruhito, met Vietnamese Vice President Vo Thi Anh Xuan on Thursday as he started his visit to Hanoi marking the 50th anniversary of diplomatic relations between the two nations.

The visit by Akishino and his wife, Crown Princess Kiko, comes at a time when Tokyo is pushing to deepen ties with Southeast Asia and other emerging nations to tackle regional and global challenges.

Akishino stressed the importance of ties between the two nations at a news conference in Japan last week and said, “I hope we can contribute as part of an effort to promote friendly relations between the two countries.”

The couple also laid a wreath at the mausoleum of Vietnam’s first president, Ho Chi Minh, and are scheduled to meet President Vo Van Thuong before traveling to Hoi An in central Vietnam.

The trip is Akishino’s third to Vietnam after earlier visits in 1999 and 2012.

Bilateral trade between the two countries was nearly $50 billion last year, making Japan the fourth-largest trading partner for Vietnam.

The couple’s visit comes three months after Emperor Naruhito and his wife Masako visited Indonesia, this year’s chair of the Association of Southeast Asian Nations, as ASEAN and Japan mark 50 years of friendship. Japan is Indonesia’s largest provider of official development assistance, according to Japan’s Foreign Ministry.