The Mastery Window lets you view your Mastery points, and allocate them however you want.
To see a description of the Mastery, simply move the mouse over the icon.
To add points to that Mastery, click on it.
The level of a specific mastery is indicated by the number to its right.
A gold border around a mastery indicates that the player has achieved maximum mastery for that weapon.
As of Patch 61, the Acclaim version of 9Dragons does not have the Advanced Masteries, and the interface will change once it is released.
On December 8th, 2008, Patch 63 introduced new Basic and Advanced Masteries. Now, Masteries have three sections : Clan Basic Mastery, Characterics of position and Kung Fu Mastery
As vagabond, the player has only access to Basic Mastery. When a clan is chosen, Basic Mastery becomes Clan Basic Mastery with some new buffs. In that case, the weapons not used by the clan is removed. The Advanced Masteries only appear when the player hits the Second Role (at Elemental Crown 6).