|“||That who controls the gauge controls the fight!||”|
"Gauge" (ゲージ Gēji) is players' resource in using card abilities. The term can also refer to the zone that holds the said resource.
At the start of the game, after both players draw their initial hand, they put the top two cards of their deck face down into the gauge without looking at them. Cards in the gauge are always face down and cannot be looked at.
Charge and Draw
At the Start Phase of each turn, after drawing the first card (if any), the turn player may choose a card from their hand and place them into the gauge. If they do, the turn player draws a card.
When paying gauge(s), choose any card(s) from the gauge, and put them into the drop zone.
In the anime, the gauge is shown as a glowing card. When a card is placed in the gauge, it's depicted as a card flying towards the gauge that expands to match the size of what's already there. If there are multiple cards, the glow becomes yellow; the cards duplicate and glow white after duplication. From Season 2 onwards, the gauge card's backing can be seen. When a gauge cost is paid, the card(s) there turn(s) into a star and move(s) towards the card demanding the gauge.