Stroke order of 力 vs 九 I'm curious as to why the stroke order of 力 is different to the stroke order of 九.

One page I found (力 and 九 stroke order) theorises that the reason is because 力 has "touching" strokes and there is a hook that "points" to the second stroke, so it could not itself be the second stroke.

This seems to be a decent theory, though I'd like to know if anybody has a concrete source proving (or disproving) this rule. It does note that it only applies for cases where the strokes touch, so it does not count in cases like 刂.

Any insights?
About this question, you can consult Guobao Wang's summary:


  1.只有横折钩类与撇相遇：先写横折钩，例刀、力、万 、方、乃、杨。 
  
  2.其他横折类与撇相遇：都先写撇，例如及（横折折撇 ），几（横折弯），九（横斜钩）、匕（竖折弯）。


translate into English:

1.Only when uppermost and rightmost lines with a left hook cross with right-to-left diagonals(ノ): uppermost and rightmost lines with a left hook is written first. For example: "刀", "力", "万", "方", "乃", "杨".

2.In other situation uppermost and rightmost lines cross with right-to-left diagonals(ノ): right-to-left diagonals is written first. For example: "及", "几", "九", "匕".

Anyway, maybe the following links will offer you more information about stroke order rules.

1.现代汉语通用字笔顺规范(official version);

2.现代汉语通用字笔顺规范.pdf;

3.现代汉语通用字笔顺规范;

4.《现代汉语通用字笔顺规范》电子版;

5."火"的笔顺.

Besides, the website 汉典 is perhaps useful to you.