How i can unlock the border?

[betamus7]

to the wuxian mountain

[Chrisme]

To discover it on the map you need to go to the crossroads in Nameless region and exit the map to the south.

To open the border you must either fight the guards, use the imperial token or get a letter of recommendation from both throne successors (Duke Kang and Duke Qui). Kang only requires somewhat ok relationship afaik but Qui will only give you the letter after you passed all the quiz exams (the one reason why he will always get stabbed by me).