FreeCell Two Decks: the bigger board, measured
FreeCell Two Decks takes everything familiar about FreeCell — every card face up, free cells to park cards in, building down in alternating colours — and doubles it: 104 cards, ten columns, eight free cells and eight foundations. The question we set out to answer was simple: does the bigger game stay as winnable as ordinary FreeCell?
Our solver, which sees every card just as you do, won 88.0% of 400 deals outright, proved none of them impossible, and ran out of search time on the remaining 12.0%. So somewhere between 88% and 100% of deals can be won, and we found no deal that cannot. The peer-reviewed St Andrews study does not include this game, so these are our own figures with nothing published to check them against.
Our figures, and what there is to compare them with
| Measure | FreeCell Two Decks (ours) | Deals | Published (St Andrews) |
|---|---|---|---|
| Solved by our solver | 88.0% (95% range 84.4–90.8%) | 400 | Not studied |
| Proven impossible | 0 deals (range 0–0.95%) | 400 | Not studied |
| Undecided when the search limit was reached | 12.0% | 400 | – |
| Length of the first solution found | about 148 moves | 352 solved deals | – |
| Deals with an Ace free on the first move | 55% | 400 | – |
| For comparison: one-pack FreeCell, solved | 99.68% | 10,000 | 99.998881% winnable |
Why is the "solved" share lower than for one-pack FreeCell? Not because the deals are worse, as far as we can tell, but because the game is much bigger to search. With 104 cards, a solution runs to around 148 moves, and our solver had to give up on some deals before finding one. Not a single deal was shown to be hopeless.
How the game is laid out and played
The deal
Two packs are shuffled together and dealt face up into ten columns: four columns of eleven cards and six of ten. Above them sit eight empty free cells and eight foundations, two for each suit.
Moves
- Build down in the columns in alternating colours: a black 6 on a red 7.
- Any exposed card may be moved into an empty free cell, one card per cell.
- Any card may go into an empty column.
- Foundations are built up in suit from Ace to King. With two per suit, both Aces of a suit can start a pile.
Winning
Move all 104 cards to the foundations.
Playing better, based on what we found
Expect a long game
At about 148 moves for the first solution our solver found, this is more than twice the length of an ordinary FreeCell solution (about 62 moves in our one-pack study). Pace yourself.
Assume the deal is winnable
We found no impossible deal in 400. If you are stuck, the likelier explanation is an earlier choice, so step back with Undo rather than starting again.
Eight cells are generous — don't waste them
Having eight free cells is a luxury, but in a 104-card game you will need them. Treat each one as working space and try to empty it again soon.
Look for the early Aces
In just over half our deals (55%), at least one Ace sat at the bottom of a column and could go straight up. When none is free, work towards the least-buried Ace first.
Clear a column
Because any card may fill an empty column, an empty column is the most flexible space on the board.
Playing on solitaire-free.uk
The game is free and runs in any modern browser, on a computer, tablet or phone, with nothing to install and no account. Cards are large and clear and there is a zoom control, which helps with ten busy columns. You have Hint, unlimited Undo, Restart and Auto Play, and you can drag or tap to move cards. Wins, time and moves are tracked for the current game, sound can be turned off, and there is a fullscreen mode with a choice of table colours.
How we ran the research, step by step
- Rules from our code. We read the site's two-pack FreeCell code: 104 cards in ten columns (four of 11, six of 10), eight free cells, eight foundations, alternating-colour building, any card into an empty column.
- Rebuilding it. We added the two-pack game to our FreeCell program and built a solver for it.
- Tuning, then testing on fresh deals. The solver's search settings were adjusted on deals 1 to 8, so to keep the test fair we measured it on different deals: 101 to 500.
- The solver. Nothing is hidden in FreeCell, so the solver sees exactly what you see. It searched up to 150,000 positions per deal.
- Why 400 deals. Each two-pack deal takes far longer to search than a one-pack one, so we ran 400 rather than thousands. That is why the range is wider than on our other pages.
- Checking against published research. The St Andrews study (Blake and Gent, Journal of Artificial Intelligence Research, 2026) covers one-pack FreeCell but not this game, so there is no published number to test ours against.
- The margin of error. The 95% range for "solved" runs from 84.4% to 90.8%; for "proven impossible" it runs from 0% to 0.95%.
- What the numbers cannot say. "Undecided" means the solver ran out of search, not that the deal is impossible. The true share of winnable deals lies somewhere between 88% and 100%.
Behind the numbers: the code
The solver is written in Python 3.11 using only the standard library, in a module called freecell2.py, which also handles Eight Off. It is a best-first search: it always looks next at the most promising position, keeps a record of positions already seen so none is searched twice, and makes only foundation moves that are provably safe. A shared runner spread the 400 deals over the cores of one machine with Python's multiprocessing; the run took about ten minutes. Ranges use the Wilson score interval. Claude, Anthropic's AI assistant, helped us write and review the solver and draft this page. The figures come from running the solver, not from the AI.
Frequently asked questions
Is FreeCell Two Decks harder than FreeCell?
It is longer and needs more planning. On winnability we found no impossible deals in either, but our solver settled fewer two-pack deals within its search limit.
Why do you give a range and not one number?
Because 12% of deals were left undecided. They might all be winnable, or some might not be, so the honest answer is 88% to 100%.
How many free cells are there?
Eight, twice as many as in ordinary FreeCell.
Has the two-pack game been studied elsewhere?
Not in the St Andrews study, and we have not found a reliable published figure.
What should I play if I like this?
Try one-pack FreeCell, Eight Off with its eight cells, or the two-pack Solitaire Double. Every game is on the games page.
By Admin, solitaire-free.uk. Study date: 19 September 2026.