Solitaire Double: two packs, a longer game and far more wins
Solitaire Double is Klondike played with two full packs shuffled together: 104 cards, nine columns and eight foundations. The building rules are the familiar ones, but the game lasts about twice as long, and it is a great deal more forgiving. In our study, a simple computer player won 81.5% of two-pack deals, compared with 42.3% in single-pack Klondike.
If you have a bit more than a quick break, say a lunch hour or a slow evening, this is the Klondike to reach for. Here is how it works, how long it takes, and why the second pack makes such a difference.
Solitaire Double by the numbers
| What we measured | Solitaire Double | Single-pack Klondike (Turn 1) | Based on |
|---|---|---|---|
| Moves in a won game (including stock taps) | about 268 | about 126 | 8,145 and 4,229 wins |
| Trips through the stock in a won game | 2.7 | 2.3 | same wins |
| Deals won by a simple player | 81.5% (range 80.7–82.2%) | 42.3% (range 41.3–43.3%) | 10,000 deals each |
| Aces that start face down | 2.8 of 8 | 1.6 of 4 | 10,000 deals each |
| Deals with no move among the face-up cards | 2.7% | 8.6% | 10,000 deals each |
The "simple player" sees only the face-up cards and never undoes a move, so its win rates are floors. A careful human does better.
How Solitaire Double is played here
Nine columns, eight foundations
- Nine columns of 1, 2, 3 and so on up to 9 cards, with only the bottom card of each face up. That is 45 cards on the table.
- A stock of the remaining 59 cards.
- Eight foundations, two for each suit.
What you can and cannot do
- Build down in the columns in alternating colours: red on black, black on red.
- Face-up runs can be moved together.
- Only a King, or a run starting with a King, may go into an empty column.
- The stock turns one card at a time, and you can go through it as often as you like.
- Each foundation is built up by suit from Ace to King. Fill all eight and you have won.
On this site Solitaire Double is always a one-card game. The Draw 3 option on its page takes you to the single-pack Solitaire Turn 3 instead.
What the extra pack changes
It looks like double the work, and it is. But it is not double the difficulty.
- Two homes for every card. With two foundations per suit, a card has twice as many places to go, so you are less often stuck waiting for one particular card.
- Two of every card for building. If one black 8 is buried, the other might be free, so a red 7 rarely has nowhere to go.
- A better start. Only 2.7% of our deals had no move at all among the nine face-up cards, against 8.6% in single-pack Klondike.
The catch is length. A single-pack win took our player about 126 moves; a two-pack win took about 268. That is why this game suits a longer sitting.
Getting through a long game efficiently
Reveal the long columns first
The ninth column hides eight face-down cards. Freeing those early matters more than tidying the short columns, because the long columns hold most of the face-down cards, and with them most of the 2.8 Aces that start hidden in an average deal.
Spread cards across both foundations
You have two piles for each suit. Keep both moving rather than racing one to King, so either copy of a low card always has a home.
Keep an eye on the pass count
Winning games needed only 2.7 trips through the stock on average. If you are on your fifth pass with nothing new happening, try a different order with Undo.
Use Auto Play at the end
With 104 cards, the final clean-up is long. Once every card is face up, Auto Play sends the rest home and saves a lot of tapping.
Playing Solitaire Double on a small screen
Nine columns and eight foundations are a lot to fit on a phone. Turn the phone sideways, use the zoom control, and tap a card then its destination rather than dragging. Fullscreen mode clears away the browser bars. On a tablet or computer the full layout fits comfortably.
Where Solitaire Double sits among the long games
If you are choosing a game for a longer sitting, it helps to compare how much work a win takes. These are the averages from our study for games where we recorded winning routes:
| Game | Moves in a win (average) | How it was measured |
|---|---|---|
| Solitaire Double | about 268 | Simple player, 8,145 wins |
| Forty Thieves | about 277 | Look-ahead player, 174 wins |
| FreeCell Two Decks | about 148 | Solver's first route, 352 deals |
| Klondike, Turn 1 | about 126 | Simple player, 4,229 wins |
Solitaire Double and Forty Thieves take a similar number of moves when they are won. The big difference is how often that happens: our players won 81.5% of Solitaire Double deals but only 5.8% of Forty Thieves deals. If you want a long game that usually ends well, Solitaire Double is the one.
How we did the research, step by step
In September 2026 the solitaire-online.nz team added Solitaire Double to its study, to find out how long a two-pack game takes and how often it can be won.
- Rules from the site code. We read the code behind this page. It uses a Klondike engine fixed at 104 cards, with nine columns of 1 to 9, a 59-card stock, one card per turn and unlimited passes. We also confirmed that the page's Draw 3 option leads to single-pack Turn 3, so only Turn 1 applies here.
- The game as a program. We took our single-pack Klondike player and extended it to nine columns and two foundations per suit.
- Numbered deals. 10,000 two-pack shuffles, seeds 1 to 10,000, so the test can be repeated deal for deal.
- A simple player. It sees only face-up cards and never undoes a move. Its 81.5% is a floor for what a careful person can reach.
- Counting. For each of the 8,145 wins we recorded the moves and stock passes. For every deal we also counted buried Aces and opening moves.
- Checking against published work. We found no published figure for two-pack Klondike, so there is nothing to compare against. That makes this result our own.
- Error bars. The 81.5% has a 95% range of 80.7% to 82.2%.
- Limits. We did not run a solver that sees every card for Solitaire Double, so we cannot say how many deals are winnable with perfect play, only that at least this many can be won without peeking.
The technical side
The code is Python 3.11, standard library only. Solitaire Double has its own module, doubleklondike.py, which reuses the priority-list player from our Klondike code: foundation plays first, then moves that turn over hidden cards, then Kings into empty columns, then waste plays, then drawing from the stock. runner.py spreads the deals across the computer's cores with Python's multiprocessing. The whole 10,000-deal run took about 5 seconds, and the 95% ranges are Wilson score intervals. Claude, an AI assistant from Anthropic, helped us write and review this code and draft the page. Every figure above comes from running the code, not from the AI.
By Admin, solitaire-online.nz. Study date: 19 September 2026.
Short answers before your next deal
How long does a game of Solitaire Double take?
Roughly twice as many moves as single-pack Klondike: our player's wins took about 268 moves against 126. Plan on a longer session.
Is it easier than normal Solitaire?
Yes, by a wide margin. Our simple player won 81.5% of two-pack deals and 42.3% of single-pack ones.
Can I play Solitaire Double turning three cards?
Not on this site. The Draw 3 option switches you to the single-pack Solitaire Turn 3.
Why are there eight foundation piles?
Two packs means two of every card, so each suit gets two piles from Ace to King.
What else is good for a long session?
FreeCell Two Decks and Forty Thieves also use two packs. See every game on the games page.