YOKOHAMA — More than 3,400 people gathered Sunday for a ceremony marking the 150th anniversary of the opening of Yokoyama port and its role as Japan's gateway to the West.

Emperor Akihito and Empress Michiko as well as Prime Minister Taro Aso were among the dignitaries at the Pacifico Yokohama convention center for the celebration of the nation's largest port.

Mayor Hiroshi Nakada said the 150th anniversary will be a year for Yokohama to reflect on and appreciate the port town's rich history, while vowing to improve its functions as a port and convention host. Next year the city will be the venue for the Asia-Pacific Economic Cooperation meeting.

"Yokohama has been built on a history full of challenges. Our seniors have made Yokohama into what it is today by meeting these challenges, overcoming hardships and preserving traditions. . . . We promise to continue meeting challenges in the future," Nakada said.

Guests included envoys from the United States, United Kingdom, the Netherlands, Russia and France — the five nations that signed trade agreements with the Tokugawa shogunate in 1858 that led to the opening of the port a year later.

Gerard Collomb, mayor of Lyon, France, one of Yokohama's eight sister cities, said the international community coming together to celebrate Yokohama's success at this time of economic crisis sends a message against protectionist trade policies.

Ambassadors from around 30 African countries who participated in the Tokyo International Conference on African Development, held last year in Yokohama, also attended the event.

The ceremony was followed by a show on Yokohama's 150 years staged by celebrities with ties to Yokohama, as well as 500 Yokohama residents. The show was produced by Amon Miyamoto, who was nominated in 2004 for a Tony Award.