平安時代前期に天皇の命令の下、優れた和歌を集めた『古今和歌集』がつくられました。しかし、そこに収められた和歌の読み方や語句の意味は難しく、誰もが理解できるものではありませんでした。そこで、東氏のような和歌の家系が独自に解釈し、師から弟子へと伝えてきたのが『古今伝授（こきんでんじゅ）』です。門外不出の秘伝であり、東氏9代目・常縁（つねより）が『古今伝授』のスタイルを完成させたといわれています。
During the early Heian period (794-1185), the Emperor of Japan ordered the creation of the "Kokin Wakashū," (Collection of Japanese Waka poems of ancient and modern times. “modern times” means “up to the Heian period”) However, the pronunciation and the meanings of the words in the waka in that collection were so difficult that they could not be understood by anyone. The “Kokin denju” are the original interpretations by the waka masters from the Tō clan, imparting them to their apprentices. As a well-kept secret, the 9th head to the Tō clan, Tsuneyori, is said to have perfected the style in the "Kokin denju".
