02
Changing names and conventions
An older word can mean something else
The Edo-Tokyo Museum’s reference answer finds no settled origin date. Earlier texts may use seiza to mean the correct seat for their own period, including cross-legged or one-knee positions. The posture’s existence, formalisation and name must be distinguished.
The posture and its name have separate histories
Edo-Tokyo Museum presents a view that the kneeling posture became more widespread during the Genroku and Kyōhō eras of the Edo period. It also cites Kumakura Isao’s suggestion that an 1882 school text used the term in its modern sense, alongside a different account of later standardization. A dated use of the word is not an invention date for the posture, nor evidence that every region changed its habits at once.