So what is this "Mastery" stuff?
You “master” a tank when you earn more Base XP in a single battle than the highest average Base XP earned in a single battle by 99% of players of that same tank within the past seven days.
Simply put, just try and beat the average.
This earns you threeTank Mastery emblems!
If you attain mastery in any of the featured vehicles while the Tank Mastery mission is active, you also get a +100% (2 hours) Free XP Personal Reserve!