Although Osa Masanori(長正統) (1978) introduced only 8 Hangeul letters in Tsushima Souke Bunko, it became clear that about 100 ones existed in there, by publication of Tsusima Rekishi Minzoku Shiryoukan (對馬歷史民俗資料館)(2009, 2012), catalogues of the documents in Tsushima Souke Bunko. These letters are very valuable because they show us the real image of communication between Japan and Korea in these days. Tsusima Rekishi Minzoku Shiryoukan (對馬歷史民俗資料館)`s research project team has deciphered these letters for 2 years. Some letters do not have any statement about the addresser, the receiver, the age, etc.. But we made some of them clear by referring to historical records, such as Oda Ikugorou(小田幾五郞)`s Goyoukakimonohikae(御用書物控). We also pointed out that Osa Masanori (1978) has several mistakes. But our study is also insufficient and further consideration about these Hangul letters is needed.