also: だんじょしちさいにしてせきをおなじゅうせず
after age 7, boys and girls should be kept apart
A Confucian-derived proverb stating that from around age seven, unrelated boys and girls should not sit together or interact freely. In modern Japan it is often cited as an old-fashioned moral precept rather than a practical rule.
The saying 'after age 7, boys and girls should be kept apart' is now considered an old-fashioned way of thinking.
Standard kanji form of the proverb; 七歳 is normally read ななさい in this expression.
Alternate reading with しちさい for 七歳; less common but attested.
From the Chinese classic 'Book of Rites' (Liji), later adopted in Japanese Confucian education. The exact derivation is uncertain, but the phrase has been used in Japan since at least the Edo period.