Seoul and Tokyo are expected to undertake discussions as early as next month over the details of Japan’s possible exercise of its right to self-defense on the Korean Peninsula following their first defense ministerial talks in more than four years.

Foreign Minister Han Min-koo and his Japanese counterpart Gen Nakatani met on the margins of the Asia Security Summit in Singapore on Saturday and agreed on the principle that the Self-Defense Forces can enter the peninsula only upon Seoul’s request or consent.

Related working-level consultations will chiefly take place within the framework of the Defense Trilateral Talks also involving the U.S., but separate bilateral sessions may open if necessary, Seoul officials said. The potential items on the agenda are the scope, conditions, procedure and other formalities associated with any Japanese military operation on the peninsula.

“Think of standard situations like an evacuation of Japanese nationals or wartime,” a senior official at Seoul’s Defense Ministry told reporters in Singapore. “We can take time and have sufficient discussions on such situations relevant to Japan’s exercise of the collective self-defense right on the peninsula.”

Tokyo is predicted to exert its right to collective self-defense primarily when it escorts and provides supplies to U.S. warships at sea or troops in Japan, evacuates its citizens here in a contingency or intercepts a ballistic missile heading toward the U.S.

Yet Nakatani triggered controversy after raising the possibility of a preemptive strike on North Korea under the scenario that it had launched a missile attack on the U.S. and was gearing up to fire another.

During the top defense meeting, Han sought to ensure that without Seoul’s request or agreement Japan could not conduct military activities that may “affect the peninsula’s security and our national interests,” the ministry said in a statement. Any issue related to the operation of U.S. forces in Japan and other reinforcements in a peninsula contingency must be subject to consultations between Seoul and Washington, he added.

Nakatani, in response, reaffirmed that if any operation is to unfold in foreign territory, the Self Defense Forces will secure the country’s consent “in any circumstances, according to international law,” saying the policy will naturally be applied to South Korea’s case.

His remarks marked Tokyo’s confirmation of the fundamental condition of Japanese troops’ entry here at the highest level yet.

The consultations, the first since January 2011, however, apparently failed to build consensus over the details on an attack against North Korea. While Han stressed that North Korea is part of South Korean territory and thus any Japanese operation requires Seoul’s consent, Nakatani did not give a clear endorsement, saying simply that Han’s view was well accepted yet he could not answer immediately, officials said.

Despite mounting pressure from Washington for a thaw, the session highlighted persistent historical tension between the top two U.S. regional allies.

South Korea has pledged to separate practical cooperation with Japan and historical and territorial rows under the so-called two-track approach. Yet it remains lukewarm about Tokyo’s offer, reiterated by Nakatani at the meeting, to clinch bilateral pacts on intelligence sharing and logistical support amid vehement political and public resistance over military cooperation with the onetime occupier and Prime Minister Shinzo Abe’s unbridled attempts to whitewash wartime history.

Following the last-minute cancelation of the signing of their info-sharing pact in June 2012, the two countries resorted last December to a trilateral “arrangement” with the U.S., citing Pyongyang’s growing nuclear and missile threats.

In Singapore, Nakatani raised eyebrows when he thanked U.S. Secretary of Defense Ashton Carter at the outset of their own bilateral talks for helping make the Korea-Japan session possible.

In their three-way meeting the same day, Han, Carter and Nakatani re-emphasized their steadfast opposition to the communist country’s continuing development of atomic weapons and delivery means in the wake of its recent ejection test of a submarine-launched ballistic missile. They agreed to work more closely together to deter any provocation including through the implementation of the intelligence accord, the ministry said.

Han, for his part, also met Carter separately to review the cross-border situation and other alliance issues. With the two countries set for a summit next month in Washington, they agreed to develop their responses to Pyongyang’s nuclear and conventional military threats and reinforce their joint defense posture, the ministry said.

“The two ministers concurred that North Korea’s provocations including the SLBM underwater ejection test pose a grave threat to peace and stability of not only the peninsula but Northeast Asia and the world,” it said in a press release.

By Shin Hyon-hee (heeshin@heraldcorp.com)