[thaumasiotes]

> Chinese use 星期一 / "weekday one" for Monday.

Well... it's true that Chinese generally consider Monday the beginning of the week, but that's not evidence. The days of the week are 一 (1)、二 (2)、三 (3)、四 (4)、五 (5)、六 (6) and 天 or 日 (day). Does day come before 1 or after 6 when you count?

edit: the map lower down in the thread ( https://en.wikipedia.org/wiki/Week#/media/File:First_Day_of_... ) shows China as beginning its week on Sunday. That does not agree with my experience, or with the Chinese people I've asked this question of.