Japan and South Korea are working toward making aircraft refueling support a regular arrangement, sidestepping a formal defense agreement that public opinion in Seoul makes difficult to conclude.

What happened: Japan's Air Self-Defense Force provided refueling support to South Korea's Black Eagles aerobatic team in January at Naha Air Base in Okinawa. Japanese and South Korean defense authorities are now considering making this refueling support a regular arrangement, with discussions expected when Defense Minister Shinjiro Koizumi visits South Korea for talks with counterpart Ahn Gyu-back.

Why it matters: Seoul requested Japanese refueling support instead of using Taiwan—where the Black Eagles had refueled before—to avoid upsetting China. Japan has long sought a formal acquisition and cross-servicing agreement (ACSA) with South Korea to streamline such operations, but South Korean President Lee Jae Myung stated on June 8 that although an ACSA is practically necessary, public sentiment in South Korea makes it difficult to conclude with Japan. By regularizing individual refueling initiatives instead, Japan hopes to build bilateral security cooperation without pursuing a formal agreement for now.

What to watch: South Korea hopes to continue receiving Japanese refueling aid for overseas missions, with the Black Eagles scheduled to participate in an air show in the Czech Republic in September.