1600 if i remember correctly.
Not sure if they will do it on the english version later in the future, but for the chinese version, your rank resets by the first day of the month if you are a six paths sennin, and you'll receive prizes in accordance with your rank

so far my garde is 2200 six paths 3 stars no more reward after u reach six path

do you move up and down ranks every battles you win and lose. ik you move up if you win but do you move down if you lose?