Forty Thieves is the patience game for people who want a real fight. Two full decks, strict same-suit building, and single-card moves combine to make it one of the toughest solitaires in common play — which is exactly why it has so many devoted fans. This page is a complete reference to the rules: the deal, the objective, the legal moves, the stock, and how you win. If you'd rather learn at the table, you can play Forty Thieves right away.
What is Forty Thieves?
Forty Thieves is a solitaire game played with two standard decks shuffled together — 104 cards in all. It takes its name from the forty cards dealt face up into the tableau at the start. The table has three areas: ten tableau columns where you do your untangling, a face-down stock with its face-up waste pile, and eight foundations where the winning piles are built. The double deck and its strict rules give the game a reputation for being unforgiving, and clearing one is genuinely satisfying.
The deal
Shuffle the two decks together and deal ten tableau columns of four cards each, all face up. That is 10 × 4 = 40 cards on the table, which is where the name comes from. The remaining 64 cards form the stock, placed face down to one side. The eight foundations all start empty. Because every tableau card is face up, you can read the whole layout from the first move — the only hidden cards are the ones still waiting in the stock.
The objective
You win by building all eight foundations up by suit, each running from Ace to King. Because you are playing two decks, there are eight foundations — two for each suit — and each fills with thirteen cards. When every foundation holds a complete Ace-to-King suit, all 104 cards are home and the game is won.
Legal moves
Forty Thieves has a short, strict set of rules. The two that define the game are same-suit building and single-card moves.
- Tableau builds down in suit. You may place a card on a tableau column only if it is the same suit as the top card and exactly one rank lower — a 9♠ goes only on a 10♠, never on a 10 of another suit. This is far more restrictive than the alternating-colour building you may know from other games.
- You move one card at a time. There is no group or sequence move. To shift a run you relocate its cards one by one, using other columns and empty spaces as relays and rebuilding the run where you want it.
- Foundations build up by suit from the Ace. A card goes to a foundation only if it is an Ace starting an empty foundation, or the next rank up in the same suit as that foundation's top card.
- An empty column accepts any single card. When a tableau column is cleared, you may place any one card there — a precious resource, since empty columns are your main tool for shuffling cards around.
The stock and waste
When you run out of useful tableau moves, you turn the stock one card at a time onto a face-up waste pile. The top card of the waste is always available to play to a foundation or onto a tableau column, but the cards beneath it are locked until you deal past them. Crucially, there is no redeal: once the stock is used up, it is gone for good. Every flip is a one-way decision, so think before you dig — a card buried in the waste, or one you fail to use when it surfaces, may never come back.
Why Forty Thieves is hard
Three rules stack against you. Same-suit building means a 9♠ will only sit on a 10♠ — your options at any moment are narrow. Single-card moves mean even a short run takes several careful steps and several free spaces to relocate. And the no-redeal stock punishes any card you misplay or fail to use in time. Taken together, only a relatively low share of deals are winnable even with good play. That difficulty is the appeal: every game won is earned, and the planning rewards patience.
How you win
The game is won the moment all 104 cards sit on the eight foundations — two complete Ace-to-King runs per suit, eight in all, every one built cleanly. The tableau and the waste end up empty and the stock exhausted. Get there and you have beaten one of solitaire's sterner tests; if you don't, undo is there to back up and try a different line.
Frequently asked questions
How many decks does Forty Thieves use?
Two. You shuffle two standard 52-card decks together for 104 cards in total, which is why there are eight foundations — two of each suit — rather than the usual four. The extra deck is a large part of what makes the game so demanding.
Can you move more than one card at a time?
No. Forty Thieves only ever moves a single card between tableau columns. To relocate a run you move its cards one at a time, parking them on other columns or in empty spaces and rebuilding the run elsewhere. That restriction, combined with same-suit building, is what makes the game so tight.
Can you redeal the stock?
No. You turn the stock one card at a time onto the waste pile, and once the stock is exhausted it is gone — there is no redeal. Every card you flip is a card you may never see again, so the order you take from the waste matters a great deal.
Keep going
Now that you know the rules, play Forty Thieves and see how far you can get. When you want a gentler two-deck-strength challenge, try the open layout of FreeCell or the spacious Eight Off, or browse everything in our guides hub.