Player vs. Base
From Starsonata Wiki
PvB is the abbreviation of "Player vs. Base". It often refers to when players attack bases, with discussion revolving around the strategy used and the difference of levels between what bases you can and can not attack. Note that the normal Player vs. Player level restrictions apply to PvB as well.
The administrators have identified PvB combat as one of major difficulties in balancing Player vs Player combat.
