"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).

revisionism

the diagram above; the top illustration

theoretically

medically, (from) a medical standpoint

first half; upper half

cover; covering

tilde; over-line

(as a) matter of fact; actually; in reality; de facto

(military, of the Korean People's Army) a colonel general