Japanese Prime Minister Sanae Takaichi and South Korean President Lee Jae-myung shake hands ahead of their summit, Jan. 13, Nara City. (©Pool photo)
With Sanae Takaichi and her ruling bloc securing renewed authority in the February Lower House election, attention in Seoul has turned to a perennial question: Will South Korea–Japan relations hold steady under two ideologically opposite leaders?
So far, the answer appears to be yes. Contrary to some media alarmism about looming friction between Japan's conservative nationalist and South Korea's left-wing president, Lee Jae-myung, bilateral ties have remained surprisingly composed.
Tokyo's recent decision not to send a cabinet-level representative to this year's Takeshima Day ceremony, alongside Lee's determination not to tilt toward Beijing as many had predicted, suggests a shared instinct for pragmatism over provocation.
Dr Choi Eunmi, a research fellow at the Asan Institute for Policy Studies, said both governments are "elevating practical cooperation and national interest above contentious issues," but stressed that "close communication, especially on the security domain, is vital for the relationship's longevity."
She elaborated on these views in an interview with JAPAN Forward.
How do you expect Japan and South Korea's relations to evolve in the near term?
Bilateral relations are highly likely to remain on their current stable trajectory. Within Japan, South Korea is widely viewed as a necessary cooperative partner, and Japanese leadership is likely to continue managing the relationship with this practical recognition in mind.
As political uncertainty in Japan recedes, existing channels of cooperation — such as summit diplomacy, foreign-policy consultations, and defense and security dialogues — are expected to remain broadly stable.
That said, latent risks persist. These include symbolic flashpoints such as history and territorial disputes, debates over the expansion of Japan's defense role, and domestic political moves aimed at mobilizing conservative constituencies.
Continued political stability in Japan could, of course, increase the predictability of its foreign policy, benefiting the bilateral ties. At the same time, Japan's defense strengthening and role expansion may carry policy and emotional reverberations within South Korea, making prior consultation and communication all the more essential.
How is Japanese public opinion shaping the country's security policy, and what does this mean for bilateral security cooperation?
The election outcome suggests that Japanese society favors a "managed expansion of responsibility" over overt militarization. This preference is likely to translate into a gradual, institutionalized enhancement of Japan's security role within the frameworks of the United States–Japan alliance as well as South Korea–US–Japan trilateral cooperation.
Recent messaging by Japan's defense minister has consistently emphasized that Japan's security judgments and responses are sovereign decisions. What this signals is that even as Tokyo deepens cooperation with allies and partners, it seeks to position itself as the primary agent of its own security policy.
In other words, under the Takaichi Cabinet, Tokyo may be shifting from near-complete reliance on the United States toward a more assertive regional role. Such a recalibration could reinforce mechanisms for coordinated responses to the region's most pressing security challenges, from North Korea's nuclear advances to rising tensions in the Taiwan Strait and China's expanding maritime footprint.
What is your assessment of Japan's expanding role in the Northeast Asian security order?
Japan's expanding security role appears to be an irreversible trend. Persistent tensions in the Taiwan Strait, China's ongoing rapid military buildup, and North Korea's advancing nuclear and missile capabilities have created a structural environment in which Japan can no longer remain a passive security actor.
In this context, Tokyo is likely to sustain a trajectory of strengthened deterrence anchored in the US–Japan alliance while contributing to regional stability through substantive trilateral security cooperation with Seoul and Washington.
What implications does Tokyo's evolving security posture have for South Korea?
The implications for South Korea are equally clear. Japan's political stability and growing security role enhance the predictability of bilateral cooperation, while also suggesting that Tokyo may adopt firmer positions when interests diverge.
The central task, therefore, is to sustain robust mechanisms of coordination and communication so that Japan's expanded role contributes to, rather than unsettles, stability in Northeast Asia.
In which areas do the two countries need additional effort to sustain stable relations?
As South Korea-US-Japan coordination deepens, differences in crisis-management perceptions and role-sharing between Seoul and Tokyo may become more pronounced, necessitating stronger institutional trust in security cooperation.
Beyond episodic diplomatic events, the two countries should develop structured medium- to long-term cooperation agendas spanning economic security, supply chains, advanced technology, climate, and subnational collaboration.
At the same time, historical issues and questions of territory and sovereignty remain ever-present triggers that can destabilize bilateral relations. Both sides, therefore, need sustained efforts to prevent the escalation and diffusion of such sensitive problems.
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Author: Kenji Yoshida
