|Shu Fa “calligraphy". Top to bottom, L to R: Seal (Zhuang) Script;|
Clerical (Li); Grass (Cao); Running (Xing); Standard (Kai)
Asks someone on Quora, and Alex answers with some interesting observations. If I’d been asked, I’d tend to say that it has something to do with the writing instruments after the development the Greater and Lesser Seal scripts which used hard tipped writing tools. After around the Han dynasty (200BCE) calligraphers began using flexible brushes. This led to standardisation of the strokes and stroke order (summarised in the character yong, 永, “forever” which has all nine). A side effect is it’s hard to write 0 with a brush -- try it and see how unnatural it feels.
Alex makes some interesting points, so copy his answer to the question below, from here: