Forty Thieves Solitaire is one of the oldest and most respected two-deck solitaire variants. Named after the Ali Baba tale, it demands patience, precise planning, and disciplined play on a board that is deliberately tight — the movement rules are strict, the stock is the only source of new cards, and every misplaced card compounds in cost over time. It is a game for players who appreciate a genuine strategic challenge.
The game uses two full 52-card decks shuffled together — 104 cards in total. From these, 40 cards are dealt face-up into ten columns of four cards each. The remaining 64 cards form the stock, placed face-down. Eight foundation piles — two per suit — are arranged in the top-right corner, waiting to be built from Ace to King.
The objective is to move all 104 cards to the eight foundation piles, building each foundation from Ace upward within a single suit. With two decks in play, each suit needs two complete Ace-to-King runs. The tableau columns serve as working space — cards are moved between them to create the sequences needed to free the cards the foundations require — and the stock is drawn one card at a time.
Forty Thieves is demanding because of what it doesn't allow: only one card can be moved at a time, tableau sequences must be same-suit and descending, and the stock cannot be recycled. These constraints make every move consequential and every wasted stock draw a cost that narrows the winning margin.
The Tableau: Ten columns, each starting with four face-up cards. All 40 tableau cards are visible from the start — there are no face-down cards. Only the top card of each column is available to move at any time. Sequences of cards cannot be moved as a unit; only one card can be physically moved per turn.
Tableau Building: Cards in the tableau are built in descending rank and same suit. A 7 of hearts goes only on an 8 of hearts; a Jack of spades goes only on a Queen of spades. Alternating colour is not sufficient — the suit must match exactly. This same-suit constraint is significantly more restrictive than Klondike's alternating-colour rule.
One Card at a Time: Only a single card — the top card of any tableau column — can be moved per turn. There is no sequence movement, no group movement. Every reorganisation move is one card at a time, making complex repositioning operations much more expensive than in games that allow sequence movement.
Empty Columns: When a tableau column is completely cleared of cards, any single card from the top of another column or from the waste pile can be placed there. Empty columns are not restricted to Kings — any card can occupy an empty column.
The Stock: 64 cards placed face-down. One card is drawn at a time onto the waste pile. Only the top card of the waste pile is available to play — to a foundation, to a valid tableau column, or into an empty column. The stock cannot be recycled: when it is exhausted, no further cards enter the game.
The Foundations: Eight piles — two per suit. Each foundation is built from Ace upward within a single suit. Cards on the foundation cannot be moved back to the tableau once placed.
Winning: All 104 cards moved to the eight foundation piles, each suit's two foundations complete from Ace to King.
Treat the stock as a scarce resource from the first draw. With 64 stock cards and no recycling, every card drawn that cannot be productively placed is buried in the waste pile. Before drawing, always scan: can the waste pile top be played? Can any tableau top move productively? Draw only when all productive moves are exhausted.
Build same-suit columns deliberately and protect them. Because tableau building is same-suit only and movement is one card at a time, building a useful tableau sequence requires multiple consecutive same-suit placements. When a same-suit sequence begins to develop in a column, protect it from being broken by cards of the wrong suit landing on top.
Prioritise foundation moves over tableau moves whenever possible. Every card that reaches the foundation is permanently out of the tableau, reducing board complexity and creating space. When a choice exists between a foundation move and a tableau move that produces a similar immediate benefit, the foundation move is almost always preferable.
Create and use empty columns as precision tools, not parking spaces. An empty column in Forty Thieves is created at significant cost. When an empty column is created, use it for a specific, planned purpose: temporarily parking one card to enable a two-step sequence, or staging a same-suit run that can't be assembled otherwise.
Think two or three moves ahead on every tableau decision. The one-card movement rule means that even simple reorganisation sequences require multiple individual moves. Before moving any card, ask: what does this placement enable or foreclose? Does it block a more valuable card that was about to be accessible?
Ali Baba is the most forgiving variant in the Forty Thieves family and the recommended starting point for players new to two-deck solitaire. The layout is identical to Forty Thieves — ten columns of four cards each — but the tableau building rule changes from same-suit to alternating colour, exactly as in Klondike. This single change dramatically reduces difficulty and is the recommended entry point to the two-deck format.
Josephine retains the same-suit tableau building rule of Forty Thieves but relaxes the movement restriction: instead of one card at a time, properly ordered same-suit sequences can be moved as a unit, exactly as in Spider. This sequence movement capability makes Josephine meaningfully more manageable than standard Forty Thieves and is the natural intermediate step between Ali Baba and full Forty Thieves.
Busy Aces takes a different approach: rather than modifying the movement or building rules, Busy Aces changes the layout. Instead of ten columns of four cards, the initial deal spreads more cards across more columns — typically twelve columns — with the goal of making more cards immediately accessible at the start. The additional accessible cards offset some of the stock dependency that makes standard Forty Thieves so demanding.
Never draw from the stock with an unplayed waste pile card available. Before drawing from the stock, always check whether the current waste pile top can be played to a foundation, placed on a valid tableau column, or used in an empty column. Drawing a new stock card when the waste pile top is playable buries a useful card and advances the stock unnecessarily.
Watch for suit concentration in the columns. Because tableau building is same-suit only, columns that have multiple cards of the same suit in useful rank order are disproportionately valuable. Recognising these concentrations early and protecting them is one of the highest-value habits in Forty Thieves.
Move Aces to the foundation immediately and track their companions. Aces go to the foundation as soon as they are accessible — this is always correct. With eight foundations to complete and two Aces per suit needed, tracking which Aces have been foundationed and which remain is essential for planning.
Use the waste pile as a planning signal. Cards that have passed through the waste pile and been played tell you what's coming. If several high-rank cards of a suit have already appeared, the remaining high-rank cards are still in the stock and will arrive in future draws. Anticipating which cards are still to come lets you prepare tableau positions to receive them.
Resist filling empty columns with the first available card. When an empty column appears, the temptation is to fill it immediately. Resist this unless the card being placed has a specific productive purpose. An empty column held open for one or two moves as a staging space is almost always more valuable than an empty column filled immediately with an arbitrary card.
Accept that low win rates are normal and adjust expectations accordingly. Forty Thieves is one of the hardest mainstream solitaire variants with typical win rates well below 50% even for experienced players. Adjusting the mental benchmark from 'I should win most games' to 'I should make fewer systematic errors each session' produces a more accurate measure of improvement.
Forty Thieves Solitaire has one of the lowest win rates of any mainstream solitaire variant, and this is by design. The combination of same-suit tableau building, one-card movement, and a non-recyclable 64-card stock creates a game where the margin for error is narrow.
With casual play — drawing from the stock reactively, making convenient but strategically costly tableau placements — typical Forty Thieves win rates fall in the 5–15% range. This is dramatically lower than Klondike or FreeCell and reflects how quickly the non-recyclable stock is consumed by unproductive draws.
With consistent application of the strategic habits above — stock discipline, same-suit column protection, foundation priority, deliberate empty column use, two-move-ahead thinking — win rates rise to 20–35%. This is still low by the standards of other popular variants, but it represents approaching the ceiling that deal quality and the game's structural constraints permit.
Research into Forty Thieves winnability suggests that a meaningful proportion of deals — estimates range from 40% to 60% — are unwinnable from the initial arrangement regardless of strategy. If your win rate with careful play sits around 25–30%, you are likely playing near the achievable ceiling for this variant.
Two full 52-card decks, shuffled together to create a 104-card game. This means there are two copies of every card — two Aces of hearts, two Queens of spades, and so on. The eight foundation piles (two per suit) reflect this two-deck structure: each suit needs two complete Ace-to-King runs to be fully foundationed.
Once. The stock in standard Forty Thieves is dealt one card at a time and cannot be recycled — when the 64 stock cards have all been drawn, no further cards enter the game. This non-recyclable stock is one of the game's most demanding constraints and is a major reason win rates are low even with careful play.
Both games use two decks and the same ten-column, four-card-per-column layout. The difference is the tableau building rule. Forty Thieves builds same-suit descending — a card goes only on a card of the same suit and the next rank up. Ali Baba builds alternating-colour descending — exactly as in Klondike. This single change doubles the number of valid tableau destinations in Ali Baba, significantly raising win rates.
Three constraints combine to make Forty Thieves uniquely demanding. Same-suit tableau building means valid destinations for each card are limited. One-card movement means every reorganisation is expensive in turns. And the non-recyclable 64-card stock means every wasted draw is permanently costly. These three constraints reinforce each other: same-suit building slows tableau progress, which forces more stock draws, which depletes the stock faster.
Before making any move, spend time scanning the opening layout: identify any Aces immediately accessible for foundation placement; spot any same-suit pairs among the ten column tops that can be consolidated; note which columns have useful same-suit concentration. Make all available foundation moves first, then consolidate same-suit runs in the tableau. Only draw from the stock once all productive tableau moves are exhausted.
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