The Sei Shonagon chie-no-ita is a puzzle that was popular in the Edo period.
シルエットパズル is a more general term for silhouette puzzles, of which 知恵の板 is a type.
Full form; the most common spelling for this puzzle.
Abbreviated spelling, also used.
From 知恵 (wisdom) + の (possessive particle) + 板 (board), literally 'wisdom board'. The term has been used since the Edo period for puzzles that test one's ingenuity.