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 (7) days.
Simply put, just try and beat the average — doing so earns you 6×Tank Mastery emblems!
If you attain mastery in one of the tanks below while the Tank Mastery mission is active, you also get a Personal Reserve for +100%Free XP (2 hours)!
Tank Mastery Missions: December 2019
MISSIONS BEGIN: December 6, 03:20 PT | 05:20 CT | 06:20 ET
MISSIONS END: January 3, 2020, 03:20 PT | 05:20 CT | 06:20 ET