"Historical kana usage", a prescriptive method of using kana to write Japanese. Devised in the Edo period by Keichū (契沖) and taught in schools until 1946, it aims to be etymologically faithful and reflects earlier stages of the language (Heian period and earlier).

Alternative spelling of 上代特殊仮名遣

By teaching, we learn. Docendo discimus.

If one learns without thinking, one will be lost in his learning. That is, if one does not think about what one learns, he will not arrive at the truth of it.