The hand size limit refers to the amount of cards a player may have in their hand at the end of their turn. The limit is six. If a player has any more than that, during that player's End Phase, they must choose cards to discard until there are only six remaining.
There are a number of cards which can influence this limit. They include:
- "Hieroglyph Lithograph": This card requires a cost of 1000 Life Points to activate, and raises the controller's hand size limit to seven for the rest of the Duel.
- "Enervating Mist": This lowers the opponent's hand size limit to five, as long as it remains on the field.
- "Infinite Cards": This removes the limit on both player's hand sizes, as long as it remains on the field.
- "Silent Wobby": This lowers its own controller's hand size limit to three, as long as it remains on the field. Its other effect is designed to help give control of it to the opponent.