During the time of King Taejong (1400 -1418), the third king of the Chosun Dynasty, Chosun was having trouble with pirates raiding villages on the east coast, including villages on Ulleungdo. To deal with the problem, King Taejong began an "empty island" policy, which involved moving villagers living on outlying islands to the mainland. Villagers from Ulleungdo were also to be moved, as the following passage in the Records of King Taejong shows:
Source:「太宗實錄」卷 六, 太宗 三年 八月 丙辰條
August 11, 1403:
강원도(江原道)의 무릉도(武陵島) 거민(居民)을 육지로 나오도록 명령하였으니, 감사(監司)의 말에 따른 것이었다.
Since there was an order to move to the mainland residents of Mu-leungdo in Kangwon Province, the governor's instructions were followed.
Notice that Ulleungdo is referred to as Mu-leungdo.
News of the new "Empty Island" policy may have reached Tsushima (Daemado) and may have been the reason for the following exchange.
Source: 「太宗實錄」 卷 十三, 太宗 七年 三月 庚午條
March 16, 1407
庚午 對馬島守護宗貞茂 遣平道全 來獻土物 發還俘虜 貞茂請茂陵島 欲率其衆落徙居 上曰 若許之 則日本國 王謂我爲招納叛人 無乃生隙歟 南在 對曰 倭俗叛則必從他人 習以爲常 莫之能禁 誰敢出此計乎 上曰 在其境內 常事也 若越境而來 則彼必有辭矣
대마도 수호(對馬島守護) 종정무(宗貞茂)가 평도전(平道全)을 보내와 토물(土物)을 바치고, 잡혀 갔던 사람들을 돌려보냈다. 정무(貞茂)가 무릉도(武陵島)885)를 청(請)하여 여러 부락(部落)을 거느리고 가서 옮겨 살고자 하므로, 임금이 말하기를,
“만일 이를 허락한다면, 일본 국왕(日本國王)이 나더러 반인(叛人)을 불러들였다 하여 틈이 생기지 않을까?”하니, 남재(南在)가 대답하기를,
“왜인의 풍속은 반(叛)하면 반드시 다른 사람을 따릅니다. 이것이 습관이 되어 상사(常事)로 여기므로 금(禁)할 수가 없습니다. 누가 감히 그런 계책을 내겠습니까?” 하였다. 임금이 말하였다.
“그 경내(境內)에서는 상사(常事)로 여기지만, 만일 월경(越境)해 오게 되면 저쪽에서 반드시 말이 있을 것이다.”
Jong Jeong-mu, the lord (수호) of Daemado (Tsushima), sent Pyeong Do-jeon with local products as tribute, and returned people who were taken captive. Jeong-mu requested Mu-leungdo with the intent of moving several villages there to rule.
The (Korean) king answered, "If I agree to this, the king of Japan may call me a traitor, and discord may develop between us."
Nam Jae answered, "The Japanese customarily believe that to betray someone means you must follow a different person. This cannot be forbidded because it is considered a curtomary part of their everyday life. Who would dare attempt such a scheme?"
The king said, "That may be considered an everyday occurence within their borders, but when they cross over into another country, something may be said about it."
The lord of Tsushima (Daemado) seems to have wanted to move villagers to Ulleungdo and asked the Korean king (Taejong) for permission to do so. Taejong, however, was worried that the Japanese king might consider such a move treasonous since the Japanese would be moving into Korean territory.
Maybe, the lord of Tsushima felt that King Taejong might agree to the plan because he had heard the Korean king was moving Korean villagers off Ulleungdo?