South Korea has asked the US Indo-Pacific Command to revise the US military’s reference to international waters between Japan and South Korea from the “Sea of Japan” to a neutral description, South Korea’s Joint Chiefs of Staff confirmed Thursday.

The navies of South Korea, the United States and Japan conducted a trilateral missile defense exercise outside the territorial waters of South Korea and Japan on Wednesday to enhance military interoperability and readiness against escalating threats from North Korea.

The US Indo-Pacific Command’s reference to the international waters where the exercise took place as the “Sea of Japan” in a statement immediately prompted a backlash from South Korean media outlets.

“We’ve asked the Indo-Pacific Command to revise its reference to the location as the Sea of Japan, which has remained unchanged,” JCS spokesperson Col. Lee Sung-jun said during a televised briefing held on Thursday morning. “We will wait for a response.”

Lee said the South Korean military expects the US Indo-Pacific Command to amend its statement in light of the contested naming of the area between South Korea and Japan. South Korea’s Defense Ministry and JCS made the requests to the US on Wednesday evening.

The US Indo-Pacific Command’s statement generated a whirlwind of local media reports raising the questions of whether it is fair to call the international waters which are not subject to any state’s jurisdiction as the “Sea of Japan.”

More than 30 local news outlets and broadcasters in South Korea highlighted the difference between the South Korean military and the US Indo-Pacific Command in specifying the spot of the trilateral exercise as of 6 p.m. on Thursday.

The JCS was asked by local media whether it was appropriate to stage the trilateral exercise around 180 kilometers east of the Dokdo islets on Takeshima Day, the day Japan annually celebrates its claim to the Dokdo islets.

This is not the first time that South Korea has asked the US to amend its reference to the location of trilateral exercises, which have been generally staged on international waters between South Korea and Japan.

In October last year, the US Indo-Pacific Command initially designated the location of the trilateral missile defense exercise in an area similar to where the Wednesday drills were conducted as the “Sea of Japan.” But the command later revised its statement and used the term “waters between Korea and Japan,” complying with a request from South Korea.

The US Pacific Fleet also took out the term “East Sea” in its press release on the bilateral naval drills staged between South Korea and the US in South Korean waters in September 2022 after Japan lodged a complaint.

The ongoing conflict on the naming reflects the sensitivity of the issue for both countries that have been at odds for years over territorial and wartime history disputes rooted in Japan’s 1910-45 colonial rule of Korea.

Tokyo insists that the Sea of Japan is the only name that has been established internationally, with no need or reason for changing it. But Seoul has been putting forward diplomatic efforts to campaign for the term East Sea, which it says has been in use for more than 2,000 years as numerous historical records illustrate.

But the waters between the Korean Peninsula and the Japanese Archipelago became widely known as the Sea of Japan as Japan emerged as a regional power in Asia in the late 19th century and the early 20th century when world maps were being drawn similarly to current ones. South Korea has elucidated that the country was unable to claim the legitimacy of the name “East Sea” during the period of the Japanese occupation.

South Korea’s Foreign Ministry said the government has repeatedly clarified its stance on using the term “East Sea,” and conveyed clear messages to the US including the US Indo-Pacific Command.

“Our government will continue to make efforts to rectify mistakes related to the reference of the East Sea and enhance the understanding of the international community on the issue in close cooperation with overseas missions, related government agencies such as Northeast Asian History Foundation and nongovernmental organizations,” Lim Soo-suk, a spokesperson for the ministry, said at a televised general press briefing in response to a question on the issue on Thursday.