The area of present-day Hiezu appears in a Heian-period dictionary compilaed in 934, the Wamyō Ruijushō, as part of the village of Mino in Aimi District.
The first truly Japanese-style encyclopedia is said to be Minamoto no Shitagō's 10-scroll work, Wamyō Ruijushō, which was written in the ancient Japanese syllabary system of man'yōgana and contained entries arranged by category.