Historical Rules · 1 May 2013
Rule 311.6
Official source text from the 1 May 2013 Rules release
Each vanguard card has a hand modifier printed in its lower left corner. This is a number preceded by a plus sign, a number preceded by a minus sign, or a zero. This modifier is applied to the maximum hand size of the vanguard card's owner (normally seven) to determine both how many cards that player draws at the beginning of the game and his or her maximum hand size.