Japan and South Korea agreed to resume regular visits between their leaders and take steps to resolve a trade dispute during a highly anticipated summit in Tokyo on Thursday, in what Japan’s Prime Minister called a “big step” to rebuild the two nations’ security and economic ties as they try to overcome a century of difficult history.

The summit could revise the strategic map of northeast Asia. The two U.S. allies, who have long often been at odds over their history, are seeking to form a united front, driven by shared concerns about a restive North Korea and a more powerful China.

Japanese Prime Minister Fumio Kishida and South Korean President Yoon Suk Yeol both stressed the importance of improved ties as they opened Thursday’s summit, hours after a North Korean missile launch and encounters between Japanese and Chinese vessels in disputed waters.

In his opening remarks, Mr. Kishida said that the meeting will mark the resumption of regular visits between the leaders, which have been on hold for more than a decade. He told a joint news conference that the countries had agreed to resume defence dialogue and vice-ministerial strategic talks, while also restarting a process of trilateral communication among Japan, South Korea and China.

Mr. Yoon said “the ever-escalating threat of North Korea’s nuclear missile program poses a huge threat to peace and stability not only in East Asia but also to the (broader) international community.”