Book counter

Book counters are a type of counter introduced in Strixhaven: School of Mages that act as resources for activated abilities. They are created via the Magecraft mechanic which means a counter is created whenever an instant or sorcery spell is cast.
==Description==
Book counters first appeared on an artifact in Strixhaven. <c>Spell Satchel</c> is the first card and artifact to use book counters. Book counters build up on the artifact whenever the player casts an instant or sorcery alluding to the artifact gaining energy from each spell cast. It then has activated abilities to either convert a book counter into one Colorless mana or multiple into a card draw. One of its abilities was rebalanced in Magic: The Gathering Arena on April 7, 2022, to allow for easier use and scaling by making it so only 2 book counters equaled a card draw rather than the 3 initially printed on the card.
==References==