Durak - Wikipedia, the free encyclopedia: "At any point during a defense, the attacker or any third party can pitch in extra attacking cards, provided that for each new attacking card, there is already a card of the same rank on the table (either defending or attacking), and the total number of attacking cards does not exceed six, five if there have been no successful defenses, or the number of cards in the defender's hand, whichever is less. The defender must also defend against these new cards"
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