”Hae Dong Che Guk ki” records only Japan and the Ryukyu Islands. Japan occupies ninety-seven percent of the book. It also contains six maps and from them one apprehends the extent of concern the Koreans had on the Tushima and Iki islands; Japanese world knowledge and Korea's, Japan's, Ryukyu's awareness of the East Asian region in the fifteenth century. This book has comprehensive observations on Japan's politics, society, customs and geography. Moreover it is the most detailed history document on Japan and Korea's foreign diplomacy in the fifteenth century.