Spider, two suits: same two decks, half the runs that can move
Two-suit Spider uses the same 104 cards as the one-suit game, now split into spades and hearts. The deck size stays put; what changes is how many of your builds can travel. Only same-suit runs move as a block, so a heart dropped on a spade turns a long run into two short ones.
That one change took our look-ahead program from 52.8% at one suit to 5.7% of 4,000 deals at two suits (95% range 5.0%–6.5%). It completed 0.82 of 8 runs per game on average (0.77–0.88). On this site's other two-deck games, the second deck adds room. In Spider, the second suit takes it away.
At a glance: two suits on 104 cards
| Measure | 2 suits | 1 suit, for comparison |
|---|---|---|
| Program win rate | 5.7% (5.0–6.5%), 4,000 games | 52.8% (51.2–54.3%), 4,000 games |
| Runs completed per game, of 8 | 0.82 (0.77–0.88) | 4.96 (4.86–5.07) |
| Games with at least 4 runs completed | 6.3% (5.6–7.1%) | 56.9% (55.4–58.5%) |
| Moves in won games | 154.6 (152.4–156.8), 228 wins | 117.5 (117.1–117.9), 2,111 wins |
| Emptied a column before the first deal | 0.5% (0.3–0.8%) | 1.3% (1.0–1.7%) |
| Won when that happened | 71.4% (50.0–86.2%), 15 of 21 | 98.1% (89.9–99.7%), 51 of 52 |
The program is weak at this level; treat 5.7% as a floor. There is no one-deck two-suit Spider on the site and no published figure for this level, so we cannot say how a one-deck version would compare.
Where the second deck still helps
Two decks mean two 8s of hearts and two of spades. When a 7 of hearts needs a home, there are two same-suit 8s to aim for, not one. Choosing the right twin is the main way to keep runs clean.
The rules here
- Cards: two decks, 104 cards, spades and hearts.
- Layout: ten columns of six and five, bottom card face up.
- Stock: 50 cards in five deals of ten; no dealing onto an empty column.
- Building: any card on one rank higher, any suit.
- Moving: only same-suit runs move as a block.
- Empty columns: any card or movable run.
- Completed runs: a same-suit King-to-Ace run leaves the table.
Playing two suits well
Build in suit when there is a choice
Two twin 8s, one red and one black, both take your 7 of hearts. Pick the heart. An off-suit build is a loan against a future empty column.
Keep mixed builds short
A mixed run can only be taken apart piece by piece. Short ones are cheap to fix.
Aim for one finished run
The program completed fewer than one run per game on average. A single finished run gives back 13 cards of space.
An early empty column is still gold
Rare (0.5% of games), but the program won 15 of those 21.
Use Undo freely
The program never undid anything. You can.
Spider on freecell-two-decks.com
Free in any modern browser on computer, tablet or phone, with no account. Hint, unlimited Undo, Restart, Auto Play, zoom and fullscreen, drag or tap to move, a count of wins, time and moves, and settings for sound and table color.
How we measured it
The freecell-two-decks.com team ran these simulations in September 2026 on this site's Spider rules.
- Rules from the game code; spades and hearts for two suits.
- Deals 100,001–104,000, after tuning on deals 1–30.
- A look-ahead program using face-up cards only (up to 250 positions per turn), no Undo.
- No solver and no published two-suit figure.
- 95% ranges: Wilson score for rates, normal intervals for averages.
Python 3.11, standard library only. Claude, an AI assistant by Anthropic, helped write and review the code and draft this page; every figure comes from running the code.
Questions
Why is two suits so much harder than one?
Runs only move within a suit. Same 104 cards, far less mobility: 5.7% against 52.8% for our program.
Is 5.7% my chance?
No. It is a weak program's floor.
What next?
Go back to one suit, on to four suits, or play the site's main game, FreeCell Two Decks. Everything is on the games page.
By Admin, freecell-two-decks.com (Forty Media). Research run September 2026.