Forty Thieves Solitaire is a two deck solitaire card game where the player deals 40 cards into 10 piles and is only able to move the top card in each pile. The remaining cards in the deck are used as a stock pile, from which the player can deal a card at a time. The player can use the cards dealt from the stock pile to help build the piles, or the foundations. The player is allowed to use the top card on a pile or the waste pile to build down the other piles by suit, or build up the foundation by suit from Ace to King. When a pile is empty, any card can be used to start a new pile in the same place. The player wins when all 104 cards have been moved to the foundation.