The analysis further concluded that in granting Tsushima's So clan a seal that bore the inscription "So clan of Yugawara City" in July 1420, Joseon Korea failed to gain recognition for their sovereignty over Tsushima; if at that time Korea had refused to recognize Tsushima's autonomy, and instead sent an official to put Tsushima's government under their direct control, Tsushima would almost certainly be under Korea's territorial control today (as reported in a Rengo news broadcast of September 17, 2006).
1420年7月、李氏朝鮮が宗氏に「宗氏都都雄瓦」という印信を授け、対馬領主としての地位を認たことは失敗であり、その時に李氏朝鮮が対馬の自治権を認めず、役人を派遣して直接支配下に組み込んでいれば、現在の対馬は韓国領になっていたはずだと結論付けた（2006年9月17日聯合ニュース配信）。