During their first meeting in four years Saturday, South Korean and Japanese defense ministers agreed to strengthen joint efforts to deter North Korea’s nuclear and missile threats.

The meeting, which was held on the sidelines of the Asia Security Summit in Singapore, was scheduled to last 30 minutes but went on for about an hour. This indicated the two sides had a lot to discuss after a four-year hiatus.

South Korean Defense Minister Han Min-koo and his Japanese counterpart, Gen Nakatani, agreed to work together for the efficient implementation of the Seoul-Washington-Tokyo arrangement for sharing intelligence on the North and to seek a practical defense partnership for mutual benefits.

Earlier in the day, they held talks with U.S. Defense Secretary Ashton Carter to discuss joint efforts to thwart Pyongyang’s continued threats to regional security.

Top nuclear envoys from the three countries met in Seoul last week to fine-tune a strategy for getting the North to enter negotiations on its denuclearization with sincerity.

These security and diplomatic discussions, which were preceded by finance and trade ministers’ meetings between South Korea and Japan earlier last month, were seen as part of the groundwork to lay for President Park Geun-hye’s upcoming visit to the U.S.

Seoul may need to adopt a practical approach of decoupling disputes with Tokyo over historical issues from security and economic cooperation before Park embarks on a five-day trip to the U.S. in mid-June. She is to meet with U.S. President Barack Obama in Washington on June 16. The two countries are striving to make the summit serve as an occasion to demonstrate that their alliance remains firm in the course of the U.S. upgrading its strategic partnership with Japan to keep a resurgent China in check while letting Prime Minister Shinzo Abe backpedal on addressing Japan’s pre-1945 wartime wrongdoings.

Park’s visit comes less than two months after Abe traveled to the U.S. and ahead of Chinese President Xi Jinping’s planned trip to the U.S. this autumn.

The subtle timing of Park’s visit may lead some South Koreans to compare the way the U.S. treating Park with how it treated the leaders of Japan and China. As many diplomatic experts note, however, it may be meaningless to judge how successful Park’s visit will be in terms of protocol. The U.S. measure to receive Park in a working manner this time should not be misunderstood as disregarding the South Korean leader. Park made an official visit to the U.S. in 2013, during which she had dinner with Obama at the White House and delivered an address to a joint session of the U.S. Congress.

What is important is that Park and Obama hold candid and substantial talks in an amicable atmosphere on a broad range of issues, including security threats from Pyongyang.

It is hoped that their fourth summit since Park took office in early 2013 will result in giving critical impetus to reviving international efforts to denuclearize the North through a mixture of more pressure and more engagement. Pyongyang vowed Sunday to ensure a “balance of forces” with the U.S. by advancing its nuclear and missile capabilities. It claimed Washington is to blame for the failure of denuclearization on the peninsula. South Korea and the U.S. need to be more active in holding talks with the North to explore its true intent.

Seoul officials say Park and Obama will not address the issue of deploying an advanced U.S. air defense system on the peninsula. But their summit should help facilitate South Korea’s decision on the deployment of the system on its soil based on its own security interests.

It will also underline the depth of the South Korea-U.S. partnership for the two leaders to discuss ways to enhance cooperation in addressing global challenges such as climate change, trade and nuclear nonproliferation.