Klondike: how much does thinking ahead really buy you?
Klondike is the seven-column game with a draw pile in the corner, the one most Americans simply call "Solitaire". It is also the cleanest place to see a question this site keeps asking about every game: if you stop playing the first move that looks good and start planning a few moves ahead, how many more games do you win?
We measured both ends. A program that plays only what it can see, picks moves from a fixed priority list and never takes anything back won 42.3% of 10,000 one-card-draw deals. A search program that plans move by move, and is allowed to know where the hidden cards are, proved 76.6% of 1,000 deals winnable, with another 21.3% it could not settle in time. The distance between those two numbers, at least 34 percentage points, is the room that planning, patience and a good memory for the stock can fill.
Klondike at a glance: the floor, the ceiling and the gap
| Player on the same one-card-draw rules | Result | Deals | 95% range |
|---|---|---|---|
| Rule-of-thumb bot: face-up cards only, no Undo | 42.3% won | 10,000 | 41.3–43.3% |
| Planning search that knows the hidden cards | 76.6% proven winnable | 1,000 | 73.9–79.1% |
| Same search: still open when its budget ran out | 21.3% | 1,000 | 18.9–23.9% |
| Same search: proven impossible | 2.1% | 1,000 | 1.4–3.2% |
| Published estimate, perfect knowledge (Blake and Gent) | 90.48% | – | ±0.116% |
Read the bot's 42.3% as a floor, not as how often people win. It never undoes, never peeks and never plans. The planning search is a ceiling nobody reaches at the table, because it knows the face-down cards. A real player lives somewhere in between, and the tips below are about moving up from the floor.
The rules on spidersolitaireonline.us
- The deal: 28 cards in seven columns of one to seven, with the last card of each column face up. The other 24 cards form the stock.
- Goal: build all four suits on the foundations, Ace up to King.
- Tableau building: down by one rank in the other color, so a black 9 takes a red 8.
- Moving runs: a correctly ordered run moves as one unit if its top card fits where it lands.
- Empty columns: a King, or a run headed by a King, and nothing else.
- The stock: one card per click here, with no limit on passes; the waste turns back into the stock whenever it runs out. A draw toggle switches to the three-card game.
- Foundations: a card can be brought back down to the tableau if you need it.
Where planning earns its keep
Look before the first click
The opening layout tells you less than you might hope. In our deal check, 88.0% of deals had at least one Ace face down in the tableau (1.6 of the 4 on average), and 8.6% offered no move at all among the seven face-up cards. The bot won 44.5% of deals with no Ace hidden and 41.6% of deals with two or more hidden. That is a few points, not a verdict: how you play matters far more than how the cards fell.
Ask what a move uncovers
The bot's priority list already prefers moves that flip a face-down card, and that alone gets it to 42.3%. The step up is choosing which card to flip. Of two moves that each reveal a card, prefer the one in the taller column; it has more cards waiting under it.
Remember the stock
With one card per click and unlimited passes, every stock card is reachable on every pass. The bot's winning games went through the stock 2.3 times on average. A player who notes where the useful cards sit can plan tableau moves around them instead of turning cards and hoping.
Hold back the middle ranks
A greedy habit is to send every card home the moment it can go. Low cards are usually safe, but a 6 or 7 on the foundation may be the only landing spot a 5 or 6 of the other color had. Wait until the lower cards of the opposite color are home too.
Do not open a column you cannot fill
Clearing a column is worth it only if a King is ready to move in. Plan the King first, then empty the column.
Use Undo as your look-ahead
The planning search wins more because it tries a line, sees where it goes and backs out. You cannot see face-down cards, but unlimited Undo on this site lets you try a move, see what it reveals and take it back. That is the cheapest way to close the gap between 42.3% and the higher figures.
Built for careful play
Klondike here is free in any modern browser on computer, tablet or phone, with nothing to install and no sign-up. You get a Hint button, unlimited Undo, Restart for the same deal, Auto Play to finish a solved game, a zoom control for larger cards, and drag-and-drop or two-tap moves. Wins, time and moves are tracked for the current game, and sound, fullscreen and table color are in the settings.
How we measured the gap
The spidersolitaireonline.us team ran these simulations in September 2026 on the exact rules this page uses.
- Read our own game code to fix the rules: one-card draw, unlimited passes, Kings only in empty columns, one card allowed back from the foundations.
- Rewrote the game in Python and let the program play 2,000 test games to make sure it never broke a rule.
- Numbered every deal. Each shuffle comes from a seed, so deals 1 to 10,000 can be replayed card for card.
- Used two players. The rule-of-thumb bot sees only face-up cards, works down a ranked list of move types and never undoes. The planning search tries moves depth-first, remembers positions it has already seen and knows the hidden cards.
- Ran the deals. The bot played all 10,000. The search had 1,000 deals and up to 150,000 positions each before a deal counted as undecided.
- Compared with published work. Blake and Gent (Journal of Artificial Intelligence Research, 2026) estimate 90.48% for perfect-knowledge play, inside our range of 76.6% to 97.9%.
- Gave the uncertainty. Every percentage comes with a 95% range (Wilson score interval).
- Stated the limits. The bot is a floor; the search sees what you cannot; a fifth of deals ran out of search budget.
The code uses only the Python standard library and ran across 19 processes on one machine. Claude, an AI assistant made by Anthropic, helped us write and check the code and draft this page. Every figure comes from running the code; none was produced by the AI.
Klondike questions
Is "Solitaire" the same game as Klondike?
For most people in the U.S., yes. The default Solitaire on computers and phones is Klondike.
How many deals can be won?
Our planning search proved 76.6% winnable and 2.1% impossible, with the rest undecided. The published estimate for perfect play is 90.48%.
Why does a simple bot win less than half?
It never plans and never undoes. Each move looks fine on its own; the losses come from moves that close off better lines later.
Is there a limit on passes through the stock?
No. Recycle the waste as often as you like.
What should I try next?
The Klondike Turn 3 page shows how the three-card draw makes planning even more valuable, Solitaire Double is the two-deck version, and every game is listed on the games page. For the game this site is named after, start with Spider Solitaire.
By Admin, spidersolitaireonline.us (Solitairen OOD). Research run September 2026.