For the 10th consecutive year, the Japanese government has claimed ownership of the Korea-controlled Dokdo Island in the East Sea.
The latest claim appeared in a defense white paper released earlier this month.
But now, a recently released map shows that Japan considered Dokdo to be Korean territory right after its surrender in World War Two.
Korea's state-run Northeast Asian History Foundation revealed a scanned file of the map, which was discovered by researcher Chung Tae-man.
The map, drawn up by Japan before it signed a peace treaty with Allied forces in September of 1951, clearly excludes Dokdo from Japanese territory.
Instead, it has a semicircle surrounding the islets, indicating they belonged to Korea.
Korea argues it regained sovereignty over Dokdo, along with the rest of the Korean peninsula, after its post-war independence from Japan's colonial rule.
For years, conservative groups in Japan have claimed Dokdo was labeled their territory on the map, which was submitted to the Japanese parliament before it ratified the peace treaty.
Japanese researchers, however, never publicized it.
The map appears to offer evidence that both the Japanese government and parliament once recognized the islets as Korean territory.
What's also interesting is how Chung found the map.
He said a conservative Japanese person had posted the map, obtained from Japan's National Diet Library, on his website to prove that Dokdo was Japanese territory.
But he perhaps failed to catch the semicircle because the islets' names were written over it.
Choi You-sun, Arirang News.