Spider, one suit: a two-deck game that has always been two decks
Spider is the best-known 104-card solitaire. In the one-suit version all eight King-to-Ace runs are spades, so every ordered run can move and the two decks behave like one long, generous suit. Where FreeCell Two Decks is a one-deck game scaled up, Spider was designed around the second deck from the start: ten columns, a 50-card stock and eight runs to finish.
Our look-ahead program, which sees only face-up cards and never undoes, won 52.8% of 4,000 one-suit deals (95% range 51.2%–54.3%) and finished 4.96 of the 8 runs per game on average (4.86–5.07). We have no one-deck Spider of our own to compare with. The closest outside figure is for Spiderette, a one-deck relative: Blake and Gent (2026) report it 99.620% winnable (±0.018%) for a solver that sees every card, a different kind of measure from our program's floor.
At a glance: one-suit Spider on 104 cards
| Measure | Result | 95% range | Games |
|---|---|---|---|
| Program win rate | 52.8% | 51.2–54.3% | 4,000 |
| Runs completed per game, of 8 | 4.96 | 4.86–5.07 | 4,000 |
| Games with at least 4 of 8 runs completed | 56.9% | 55.4–58.5% | 4,000 |
| Moves in a won game, deals included | 117.5 | 117.1–117.9 | 2,111 wins |
| Won after emptying a column before the first deal | 98.1% (51 of 52) | 89.9–99.7% | 52 |
| One-deck comparison run by us | none | – | – |
Note the move count. A one-suit Spider win took about 117.5 moves, fewer than the 148.0 moves our solver needed on FreeCell Two Decks, even though both games use 104 cards. Removing each finished run shrinks the table as you go.
Spider across its three suit levels
| Level | Program won | Runs completed (of 8) | Games |
|---|---|---|---|
| 1 suit (this page) | 52.8% (51.2–54.3%) | 4.96 | 4,000 |
| 2 suits | 5.7% (5.0–6.5%) | 0.82 | 4,000 |
| 4 suits | 0.2% (0.1–0.5%) | 0.04 | 2,000 |
Adding suits, not adding cards, is what hurts in Spider. The deck size never changes.
The rules here
- Cards: two decks, 104 cards, all spades at this level.
- Layout: ten columns, four of six and six of five, only the bottom card face up.
- Stock: 50 cards, dealt one to each column, five times, no reuse. You cannot deal while a column is empty.
- Building: any card on one rank higher.
- Moving: same-suit runs move as a block, which here means any ordered run.
- Empty columns: any card or run.
- Completed runs: King to Ace leaves the table automatically.
Playing a 104-card game with one suit
Eight runs, not four
With two decks there are two of every spade. A 9 can go on either 10, so choose the one whose column you want to empty later.
Finish runs to shrink the table
Each completed run takes 13 cards off. Our program completed at least four runs in 56.9% of games; push the nearest-to-done run first.
Clear a column before dealing
It happened in only 1.3% of the program's games, but it won 51 of those 52. Treat it as a goal, not luck.
Deal into a tidy table
Each deal drops ten cards on your runs. Prepare the columns first.
Undo beats the program
Our program never took a move back. You can, which should lift you above 52.8%.
Spider on freecell-two-decks.com
Free in any modern browser on computer, tablet or phone, no account. Large cards with zoom, Hint, unlimited Undo, Restart and Auto Play, drag or tap, a counter for wins, time and moves, and sound, fullscreen and table color settings.
How we measured it
The freecell-two-decks.com team ran these simulations in September 2026 on this site's own Spider rules.
- Rules from the game code, including the check that blocks dealing onto an empty column.
- Python 3.11, standard library only.
- Tuned on deals 1–30, measured on deals 100,001–104,000.
- A look-ahead program searching up to 250 positions with face-up cards only, no Undo. Its results are a floor.
- No one-deck Spider was run. The Spiderette figure is Blake and Gent's, for a solver that sees every card.
- 95% ranges: Wilson score for rates, normal intervals for averages. The early-column figure rests on 52 games and shows association, not proven cause.
Claude, an AI assistant by Anthropic, helped write and review the code and draft this page; every figure comes from running the code or from the cited paper.
Questions
Is one-suit Spider a two-deck game?
Yes, always: 104 cards, eight runs to complete.
How often can I win?
Our program's 52.8% is a floor; with Undo and planning you should do better.
What next?
Move up to two suits, or try the site's main game, FreeCell Two Decks. All games are on the games page.
By Admin, freecell-two-decks.com (Forty Media). Research run September 2026.