Solitaire Double: two packs, nearly twice the wins
Solitaire Double is Klondike played with two full packs shuffled together: 104 cards, nine tableau columns and eight foundations. It looks bigger and slower, and it is, but it is also far kinder. When we dealt 10,000 games to a simple computer player, it won 81.5% of them. The same player wins only 42.3% of ordinary one-pack Klondike.
That makes Solitaire Double one of the friendliest long games on the site: plenty of cards to sort, plenty of places to put them, and a real chance of finishing almost every time you sit down with a cuppa.
At a glance: Solitaire Double in numbers
| What we measured | Result | Deals | How |
|---|---|---|---|
| Games won by our computer player | 81.5% (95% range 80.7–82.2%) | 10,000 | Rule-based player that sees only face-up cards and never undoes |
| Same player, one-pack Klondike Turn 1 | 42.3% (41.3–43.3%) | 10,000 | Same approach, for comparison |
| Moves in a won game, stock turns included | about 268 | 8,145 wins | Average over every win |
| Passes through the stock in a won game | about 2.7 | 8,145 wins | Average over every win |
| Aces that start face down (of 8) | 2.8 on average | 10,000 | Counted from the deal |
| Deals with no move among the 9 face-up cards | 2.7% (2.4–3.0%) | 10,000 | Counted from the deal; one-pack Klondike: 8.6% |
No published study covers two-pack Klondike, so these are, as far as we know, the first figures of their kind. The 81.5% is a floor: the computer player cannot look ahead or take a move back, and a careful person with Undo should do better.
The rules on this site
- Two packs, 104 cards. There are two of every card, so two Aces of spades, two Kings of hearts, and so on.
- Nine tableau columns of 1 to 9 cards, with only the top card of each face up. That puts 45 cards on the tableau.
- A 59-card stock, turned one card at a time onto the waste, with unlimited redeals.
- Eight foundations, two for each suit, each built up from Ace to King.
- Tableau building goes down in alternating colours, and a correctly built run may be moved as a unit.
- Only a King, or a run starting with a King, may fill an empty column.
Solitaire Double is played at Turn 1 only. The Turn 3 option on the game takes you to ordinary one-pack Turn 3 Klondike.
Why the second pack helps so much
The jump from 42.3% to 81.5% sounds odd at first. More cards should mean more chances to get stuck. In practice the opposite happens, and our numbers suggest why.
Every card has two possible homes
With two foundations per suit, a red 5 of hearts can go up on either hearts pile. On the tableau, a black 7 has four red 8s it could sit on instead of two. The more landing spots a card has, the less often a single buried card holds up the whole game.
Fewer frozen openings
In one-pack Klondike, 8.6% of deals give you no move at all among the face-up tableau cards. With nine columns showing, that falls to 2.7%. You nearly always have something to do on move one.
Buried Aces matter less
A typical deal hides 2.8 of the eight Aces. That sounds like a lot, but because each suit has two Aces, one hidden Ace rarely blocks a suit completely.
Strategy the numbers point to
Settle in for a long game
Our winning games averaged about 268 moves. That is more than twice the length of a one-pack game, so treat Solitaire Double as an evening game, not a five-minute break.
Use the stock freely, but plan each pass
Wins used about 2.7 passes through the stock. Because redeals are unlimited, there is no penalty for going round again. The real cost is time, so on each pass look for the one or two cards that unlock the tableau.
Dig the tall columns on the right
The ninth column hides eight cards. Uncovering those early gives you the most new information for the fewest moves.
Keep the two foundations of a suit roughly level
If one hearts pile races ahead while the other is stuck on a 3, you lose the flexibility that makes this game easy. Build both evenly where you can.
Kings still own the empty columns
As in Klondike, only a King can fill a space. There are eight Kings now, so before you empty a column, check which King is ready and what it will carry.
Playing Solitaire Double here
It is free, with nothing to download, install or sign up for, and it works in any modern browser on a desktop, tablet or phone. The cards are large and clear, and a zoom control makes the board bigger, which helps on a phone with nine columns to fit. Hint, unlimited Undo, Restart and Auto Play are always there, you can drag or tap to move, and wins, time and moves are tracked for your current game. Sound can be switched off, and fullscreen mode and table colours are in the settings.
How we did the research, step by step
The free-solitaire.nz team ran this study in September 2026 to find out how winnable Solitaire Double is on this site, with this site's exact rules.
- Read the rules from the game code. Solitaire Double loads its own script, which is fixed to 104 cards: nine columns of 1 to 9, a 59-card stock, unlimited redeals, alternating-colour building, runs moving as a unit and Kings only in spaces. We also confirmed that it plays Turn 1 only, because the Turn 3 option opens a different page.
- Rebuilt the game as a program. We extended our one-pack Klondike model to nine columns and two foundations per suit.
- Dealt 10,000 numbered games. Each deal comes from a seed, numbered 1 to 10,000, so the whole test can be repeated card for card.
- Chose the player. A rule-based player that sees only the face-up cards, as you do, and never takes a move back. That makes its win rate a floor, not the most that can be won.
- Ran the games and counted. Wins, moves, passes through the stock, and what each opening deal looked like.
- Looked for published figures. The main study in this field, Blake and Gent (2026, Journal of Artificial Intelligence Research), does not cover two-pack Klondike, so we have nothing to compare against. We compare with our own one-pack results instead.
- Worked out the margin of error. A 95% range means that if we repeated the test with fresh deals, the true figure would fall inside that range 95 times out of 100. For the win rate that range is 80.7–82.2%.
- Noted the limits. We did not run a solver that sees every card for this game, so we can say at least 81.5% of deals are winnable with ordinary play, but not how many are winnable at most.
The technical side
The code is written in Python 3.11 with the standard library only. Solitaire Double has its own module, doubleklondike.py, which reuses the rule-based player from our one-pack Klondike model, widened to nine columns and eight foundations. It chooses moves from a fixed list of priorities and sees only face-up cards. A shared runner.py spreads the deals across parallel worker processes with Python's multiprocessing; all 10,000 games finished in about five seconds of wall time. We calculate each 95% range as a Wilson score interval. We worked with Claude, an AI assistant made by Anthropic, when writing and reviewing the code and drafting this page. It supplied none of the figures: every number here comes from running the program, and the team checked the results before publishing.
By Admin, free-solitaire.nz. Study date: 19 September 2026.
Frequently asked questions
Will I win more often with two packs?
In our tests, yes, by a wide margin: 81.5% of games won against 42.3% for one-pack Klondike, using the same kind of computer player.
How long does a game take?
Much longer than one-pack Klondike. Our winning games averaged about 268 moves.
Can I play Solitaire Double with Turn 3?
Not on this site. The Turn 3 option takes you to one-pack Turn 3.
Why are there two Aces of each suit?
Because two full packs are shuffled together. Each suit gets two foundations, one for each Ace.
What else suits a long session?
Try FreeCell Two Decks or Diplomat, both two-pack games.