Forty Thieves: 64 stock cards and not a single second look
Klondike Turn 3, the game on our home page, is generous in one way and stingy in another: you can go round the stock without limit, but only every third card is within reach on each lap. Forty Thieves is stingy in both directions it can be. Its 64-card stock turns one card at a time and goes through once. Its tableau lets you build only in suit, and only one card at a time.
The result is one of the hardest games on the site for a program. Our look-ahead bot, which sees the face-up cards but not the stock order, won 5.8% of 3,000 deals (95% range 5.0%–6.7%). The simple Klondike bot won 10.6% at Turn 3 (10.0%–11.2%) and 42.3% at Turn 1 (41.3%–43.3%), each over 10,000 deals. The bots are different programs and both are floors; our Forty Thieves bot in particular is weak, and skilled players do better.
At a glance: Forty Thieves
| Measure (bot, does not know the stock) | Result | 95% range | Deals |
|---|---|---|---|
| Games won | 5.8% | 5.0–6.7% | 3,000 |
| Cards on the foundations at the end (of 104) | 34.3 | 33.5–35.1 | 3,000 |
| Moves in a won game (stock turns included) | 277.3 | 273.0–281.7 | 174 wins |
| An Ace is playable from the opening tableau | 57.3% | 55.5–59.1% | 3,000 |
Forty Thieves does not appear in Blake and Gent (2026), and we ran no solver, so there is no figure for how many deals are winnable. The solitairex.io site places Forty Thieves in its hardest tier, at 11% or less, but gives no method, so we note it only as a pointer.
How much of the difficulty is the stock?
We cannot split it out. We simulated only the site's rule (one card, one pass) and never tried a redeal or a three-card draw, so we have no number for what the stock alone costs. Any figure would be invented.
What the rules do show is how the stock and the table work together. In Solitaire Draw 3 a card you missed will come round again; our bot used 3.81 stock passes per win there (3.73–3.90). In Forty Thieves a card you do not place goes onto the waste, and the only way back is to play every card that lands on top of it. With in-suit, one-card building, there are few places to put stock cards, so the waste grows quickly. On average the bot got 34.3 of the 104 cards home before it ran out of moves.
Forty Thieves rules on this site
- Cards: 104 (two decks), eight foundations.
- Table: ten columns of four cards, all face up.
- Stock: 64 cards, turned one at a time to the waste, no redeal.
- Building: down in the same suit, one card at a time.
- Empty columns: any card may fill one.
- Win: all 104 cards on the foundations.
Beating a one-way stock
Clear a column first
With one-card moves, an empty column is how you move a run: card by card, through the gap. Getting one early is the most valuable thing you can do.
Play Aces and 2s at once
An Ace is playable from the opening layout in 57.3% of deals. Low cards on the foundations free the cards above them.
Turn the stock only when the table is done
Every stock card you turn can bury the one before it. Exhaust the table first, including moves to the foundations.
Keep the waste short
If the waste is growing and nothing is landing, stop and look for a column you can rebuild or clear.
Don't build long runs you cannot move
A long in-suit run is only movable one card at a time. Build it where it can stay until it goes home.
Two hard stocks, two different reasons
Forty Thieves and Klondike Turn 3 are both known as tough games, and on this site both come out low for our bots: 5.8% of 3,000 deals here, 10.6% of 10,000 there. But the reasons differ. In Turn 3 you have unlimited laps through a small stock, and the difficulty is reach: the card you want is often second or third in a group and stays out of play until the cards above it move. Our Klondike bot needed 3.81 passes per win at Turn 3 against 2.34 at Turn 1.
In Forty Thieves, reach is never the problem, since each stock card is live as it turns. The problem is that there is only one lap and the table offers few homes: in-suit building means each card has just two possible targets among the 104. A stock card that finds no home goes to the waste and may stay buried for the rest of the game. That is why the most useful skill here is managing the waste, not timing the draw.
A win, when it came, took about 277.3 moves including the 64 stock turns.
Where games are lost
The bot's average of 34.3 cards home (33.5–35.1, 3,000 deals) is the telling figure. Most games stall with two-thirds of the deck still out, which points to an early jam rather than a near miss. Compare Diplomat, where a similar one-pass, one-card stock left the bot with 76.0 of 104 cards home on average. The big differences between the two games are in-suit building and ten columns of four here, against any-suit building and eight columns of four there, not the stock.
Playing on solitaire-turn-3.com
Forty Thieves is free in any current browser on computer, tablet or phone, with no sign-up and nothing to install. You get Hint, unlimited Undo, Restart and Auto Play, zoom and fullscreen for the ten columns, drag or tap moves, a record of wins, time and moves, and sound and table-color settings.
How the figures were made
The solitaire-turn-3.com team ran these tests in September 2026 on the Forty Thieves rules read from this site's game code.
- Python 3.11, standard library only.
- 3,000 numbered deals, so every one can be replayed.
- Bot: a look-ahead over table and waste moves that does not know the stock order.
- 95% ranges: Wilson score intervals for percentages, normal intervals for averages.
- Not done: no solver, no published comparison, no stock variants.
Claude, an AI assistant by Anthropic, helped write and review the code and draft this page. It produced no figures; every number comes from running the code, and the team checked them.
Forty Thieves questions
Is it really this hard?
For our bot, yes: 5.8%. It is a weak floor, though, and we have no measure of how many deals a perfect player could win.
Can I redeal?
No. For a stock you can go round again, try Klondike Turn 3.
Similar games?
Diplomat has a one-pass stock too, but builds in any suit; our bot won 47.9% there. More on the games page and the blog.
By Admin, solitaire-turn-3.com (Forty Media). Research run September 2026.