South Korean President Lee Jae Myung and Japanese Prime Minister Sanae Takaichi are increasing diplomatic engagement, driven by shared concerns about regional uncertainty, particularly regarding Taiwan. Energy security was a key topic in their recent meeting.

When South Korean President Lee Jae Myung and Japanese Prime Minister Sanae Takaichi met on Tuesday, they had energy security atop the agenda – and something harder to name top of mind. It was their fourth meeting in six months, a pace of leaders’ encounters that analysts say reveals much about the uncertainty the two US allies are united in feeling, despite their historical grievances. The formal pretext of their latest summit was energy security. Japan and South Korea, heavily export-driven...