westtown:
You seem to have some advanced experiece on the I Ching. Especially since you can read Chinese, and browse forums in Chinese that discuss this in further depth.
I agree with most of your statement/help to readers paragraph, that you have posted. However, I am a little curious about the last two parts of your statement.
"Besides that, we also need to consider when a line has been month broken, is the element of the line kill the month element or the month element kill the line element. For example, line t is broken under month w, line w is also broken under month t. However, this two situation is different. For first situation, line t is water element and month w is fire element, water kill fire. Therefore, if this moving line t didn’t been killed by anything else, then it may be useful after passing through that month.""For second situation, it is on opposite direction, now is the month element killing the line element, the destruction is high. Even this moving line didn’t been killing by anything else, it already become almost useless."I am under the belief that both of these situations, the lines will be under the same amount of trouble, and not one in a worse situation than the other, as you have showed.
Under the strike rules, x clashes with y (enter element branch that clashes in x and y). We both agree there. However, you differentiate between one being more destructive on the other. Here I am dubious.
Although I understand where this logic comes from (destructive/control cycle, water controls fire, etc), under circumstances such as the one you've described, the most important factor I believe is the fact they are striking/clashing directly. Rather than which one under elemental rules controls the other. In Ba Zi/Four Pillars, if the month is fire, a single water (just assume it's just them two as in your example), is under control of the fire, despite the water usually controlling the fire. This I believe is the Reverse control rules. (Sorry, really crap at translating Chinese to English, bare with me

) Which I believe holds true here too.
What does your experience and what you've read think on this? Or is what you posted what you believe?
Please, note, this is a discussion on the matter (somewhat academically), and not an attack on you.
Looking forward to more posts from you.
UK Anon Hotmail User