|A patience game|
|Alternative name(s)||Solitaire, seven up, sevens|
|See also Glossary of solitaire terms|
After shuffling a standard 52-card deck (without Jokers), seven piles of cards are laid from left to right. Each pile begins with one upturned card. From left to right, each pile contains one more card than the last. The first and left-most pile contains a single upturned card, the second pile contains two cards (one downturned, one upturned), the third contains three (two downturned, one upturned), and so on, until the seventh pile which contains seven cards (six downturned, one upturned). The piles should look like the figure to the right at the beginning of every game.
The four foundations (light rectangles in the upper right of the figure) are built up by suit from Ace (low in this game) to King, and the tableau piles can be built down by alternate colors, and partial or complete piles can be moved if they are built down by alternate colors also. Any empty piles can be filled with a King or a pile of cards with a King. The aim of the game is to build up a stack of cards starting with 2 and ending with King, all of the same suit. Once this is accomplished, the goal is to move this to a foundation, where the player has previously placed the Ace of that suit. Once the player has done this, they will have "finished" that suit, the goal being, of course, to finish all suits, at which time the player would have won. There are different ways of dealing the remainder of the deck:
- Turning three cards at once to the waste, either allowing three passes through the deck or placing no limit on passes through the deck.
- Turning three cards at once, reversing the order of each group of three as the cards are dealt.
- Turning only one card at a time, but only passing through the deck once.
- Turning only one card at a time, but placing no limit on passes through the deck.
- Turning three cards at once to the waste with no limit on passes through the deck, but allowing the player to switch once to a single pass through the deck one card at a time; after that single pass, however, the player cannot go back to turning three cards at a time and can turn over no more cards from the waste.
Odds of winning
For a standard game of Klondike of the forms Draw 3, Re-Deal Infinite, and Win 52, the number of possible hands is over 7,000 trillion. About 79% of the games are theoretically winnable, but people do not win 79% of the games they start because they make a wrong move somewhere and lose the game prematurely. If one allows cards from the foundation to be moved back to the tableau, then between 82 and 91.5% are theoretically winnable. Note that these results depend on complete knowledge of the positions of all 52 cards, which a player does not possess. Another recent study has found the Draw 3, Re-Deal Infinite to have a 83.6% win rate after 1000 random games were solved by a computer solver. The issue is that a wrong move cannot be known in advance whenever more than one move is possible. The number of games a player can probabilistically expect to win is at least 43%. In addition, some games are "unplayable" in which no cards can be moved to the foundations even at the start of the game; these occur in only 0.025% of hands dealt.
There are four types of hands: winnable games, theoretically winnable lost games (the player made a selection that resulted in a lost game, but could not know what the correct selection was because the relevant cards were hidden), unwinnable games (there is no selection that leads to a winning result), and unplayable games.
There is a modified version of the game called "Thoughtful Solitaire", in which the identity of all 52 cards is known. Because the only difference between the two games (Klondike and Thoughtful) is the knowledge of card location, all Thoughtful games with solutions will also have solutions in Klondike. Similarly, all dead-ends in Thoughtful will be dead ends in Klondike. However, the theoretical odds of winning a standard game of non-Thoughtful Klondike are currently not known exactly. It has been said that the inability for theoreticians to precisely calculate these odds is "one of the embarrassments of applied probability".
One brute force attempt, based on a computer program playing 100 million (or slightly greater than 0.00000001%) of possible games predicts 8.7% win by clearing the table to the aces pile. However imperfect the algorithm is, it correctly predicted other results accurately (In about 1 in 102 games all black or all red cards were dealt. 1 x 25/51 x 24/50 x 23/49 x 22/48 x 21/47 x 20/46 =0.009834 or 1 in 101.69 deals). 
Standard Scoring in the Windows Solitaire game is determined as follows:
|Waste to Tableau||5|
|Waste to Foundation||10|
|Tableau to Foundation||10|
|Turn over Tableau card||5|
|Foundation to Tableau||-15|
|Recycle waste when playing by ones||-100 (minimum score is 0)|
Moving cards directly from the Waste stack to a Foundation awards 10 points. However, if the card is first moved to a Tableau, and then to a Foundation, then an extra 5 points are received for a total of 15. Thus in order to receive a maximum score, no cards should be moved directly from the Waste to Foundation.
Time can also play a factor in Windows Solitaire, if the Timed game option is selected. For every 10 seconds of play, 2 points are taken away. Bonus points are calculated with the formula of 700,000 / (seconds to finish) if the game takes more than 30 seconds. If the game takes less than 30 seconds, no bonus points are awarded.
Single 52-card deck
Below are some variations of the game of Klondike:
- In Agnes, the stock is dealt in batches of seven on reserve piles and every one is available. Furthermore, the bases of the foundations depends on the twenty-ninth card, which is dealt on the foundations.
- In Easthaven (a.k.a. Aces Up), twenty-one cards are dealt into seven piles of three, two face-down and one face-up. A space in this game can only be filled by a king or any sequence starting with a king, and when a play goes to a standstill, seven new cards are dealt to the tableau, one top of each pile. Easthaven may include 2 or 3 card decks.
- In Nine Across nine columns of cards are dealt, as opposed to the seven of conventional Klondike. The player can choose which cards to form the foundations; if one or more eights are exposed, for example, the player may decide to build on eights, and the piles are built up 8-9-10-J-Q-K-Ace-2-3-4-5-6-7. If eights are built on, sevens fill up spaces and so forth. The stock is dealt through one by one as many times as required.
- In Thumb and Pouch, a card in the tableau can be built upon another that is any suit other than its own (e.g. spades cannot be placed over spades) and spaces can be filled by any card or sequence.
- In Whitehead, all cards are dealt face up, building is by color (red on red, black on black), a sequence made up of cards that are of the same suit can be moved as a unit, and a space can be filled by any card or sequence.
- In Westcliff, thirty cards are dealt into ten piles of three cards, two face down and one face up. A space in this game can be filled with any card or sequence.
The game can be played with a Tarot-style 78-card deck (such as a Tarot Nouveau). There are two ways of doing this. Each has 9 increasing tableau stacks.
- Klondike Nouveau Run: use five foundations, and either use the Fool as the first card in the for the Trumps foundation, or remove it before playing. The Knight (Chevalier) appears between the Jack and the Queen.
- Klondike Tarot Evens: use 6 foundations; the usual four, and then use the red knights (cavaliers) as the royals for trumps 1-10, and the black knights as the royals for trumps 11-21.
- Michael A. Casteel's shareware version of Klondike for the Macintosh was first released in 1984, and has been continually updated since.
- A software version of Klondike, simply named Solitaire, has been included in all versions of Microsoft Windows from Windows 3.0 (1990) to Windows 7. The embedded versions of Microsoft Windows—originally called Windows CE, later Windows Mobile, and now called Windows Phone—have also included Solitaire. In Windows 8, Solitaire is no longer included by default. However, the Microsoft Solitaire Collection can be downloaded for free from the Windows Store, which includes Klondike plus 4 other solitaire games. Klondike has been added back in Windows 10.
- Klondike Deluxe AGA v1.1 for Amiga 1993
- GNOME and KDE have solitaire applications (sol and kpat) since early versions. Sol, also known as AisleRiot, has over 80 different Patience games
- Soltrio Solitaire for Xbox Live Arcade includes Klondike, for which the gamer will earn Achievements.
- Klondike is one of the games included in the modern iPod's "Extras" section.
- PySol is an open source and platform independent computer game that incorporates around 1,000 solitaire games, including card games like Klondike and other types of single-player games. It is written in the Python programming language.
- "The Odds of Winning Klondike Solitaire". Discuss.joelonsoftware.com. Retrieved 2012-08-19.
- Diaconis, Persi. "Mathematics of Solitaire". Mathematics Department and Graduate School Colloquium Archive 1998-1999. Retrieved 22 December 2011.
- as the first card is either red or black it is only the next six card to show that determine if the starting series is all red or all black so the odds are better than originally described
- "The Odds of Winning Solitaire".
- Highest Score in Windows Solitaire, Microsoft Help and Support, KB101766.
- The Probability of Unplayable Solitaire (Klondike) Games - The unpublished Monte Carlo result
- Searching Solitaire in Real Time
- CardGameHeaven's Klondike Guide
- Find out more about Klondike Solitaire
- How to play Klondike Solitaire - Draw 1 and Draw 3