The proverb has two senses and every modern dictionary carries both. The kind one is its face: to know is to suffer, and the one who does not know has a Buddha's calm, which is where the English ignorance is bliss comes in. The other is its use, said with a smile of the one person in the room who does not know, from the kabuki stage of 1864 to today.
No source names where the proverb began; it is first found as a pun in a haikai verse by 重貞 in 松江重頼's anthology 毛吹草, prefaced in 1638, and Ihara Saikaku first put it in prose in 1682, of a blind man who cannot see what is happening around him.
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