It's a territorial conflict built on historical enemity, nationalist pride and a tussle over some fast-depleting fishing grounds and some unproven natural gas reserves.
Tensions rear periodically over the two barren islands and 30 smaller rocks known as Takeshima in Japan and Dokdo in South and North Korea. The islands are also known as Liancourt Islands, which is how the islands first came to known to the Western world when French whalers named them after their ship and put them on a map in 1849.
They are claimed by Japan and both the Koreas but have been occupied by South Korea since 1954. The Korean coastguards are stationed there and some elderly Koreans live there.
What South Korea says
South Korea's claim, based on historicity, says that the Dokdo Islands were recognised by Japan as Korean territory in 1696 after a clash among fishermen at the time.
They were annexed by Japan in 1905, before it went on to colonise the Korean peninsula.
After the Second World War, Seoul says the islands were returned to South Korea under the 1951 San Francisco Peace Treaty along with other territories that Japan renounced at the time.
What Japan says
Japan says it has owned the islands since the 17th century and its sailors used the islands for fishing and a docking point.
In 1905, Japan incorporated the islands as part of its Shimane prefecture.
Tokyo says it never renounced the islands after the Second World War as it did some other territories and South Korea has illegally occupied the islands since 1954.
In August 2012, Japan proposed to South Korea that the dispute be referred to the International Court of Justice, but Seoul refused.
In 2005, members of Japan's Shimane prefecture declared 'Takeshima Day' to highlight the issue