"[1] The Kagakushū's colophon is dated 1444 CE, but does not name the dictionary's editor except for obscurely mentioning Tōroku Hanō (東麓破衲 "East-foothills Torn-robes"; possibly Hadō).
Scholars presume this was a Muromachi Period Buddhist priest because Tōroku is a variant name for Tōzan (東山 "East Mountain"), which is the location of Kennin-ji (建仁寺), the head temple of the Sōtō school of Zen.
Many Kagakushū editions have an appendix entitled Tenkaku-shōji (点画小異字 "characters differing only by one stroke") that lists pairs like ya 冶 "smelt; cast" and chi 治 "govern; regulate".
The origins of the Kagakushū, like the Setsuyōshū, are associated with an early type of Japanese textbook used in Buddhist Terakoya private schools, the ōraimono (往来物, "correspondences; model letter book; copybook").
According to Don Bailey: The Kagakushū, although only sparsely annotated, was in fact intended to serve as a small encyclopedia and textbook as well as a dictionary; the compiler, apparently realizing that many of the ōrai then in use were too detailed, cumbersome, and tome-like, condensed and abstracted from these texts in order to produce a reference tool containing minimally essential information and Chinese characters.