Once per turn, you may turn a card with an inkwell symbol from your hand into face-down ink, becoming a resource that you can turn sideways to summon characters You use 60-card decks in Constructed, 40-card decks in Limited, and the official website has an excellent "how to play" section
This colorless aura not only boosts stats and gives keywords but also spreads its combat damage to every opponent
Cheaper cycling cards like Hieroglyphic Illumination are used as a draw-2 in the midgame and a 1-mana cycler to help find lands early in the game
(In the Japanese version of the game, the Kois dont stack, so no matter how many times Koi Koi is called, the score will only ever double
You dont need to hunt for individual pieces across multiple packs
It also helps that it readies them to prevent any crackback from your opponents in challenges