Two-suit Spider: where careless building starts to cost you
Add hearts to the spades and Spider changes character. You may still put any card on a card one rank higher, but only runs of a single suit move together. From that point on, every build is a choice between convenience now and freedom later, and that is where planning earns its keep.
Our look-ahead player, the same program that won 52.8% of one-suit games, won 5.7% of 4,000 two-suit deals (95% range 5.0–6.5%). Yet in the 21 games where it opened up an empty column before the first deal, it won 15, or 71.4% (50.0–86.2%). Same player, same rules: roughly twelve times the win rate once early planning paid off.
This page shows what those numbers say about strategy, the rules as played here, and how we ran the study.
At a glance: two suits and the value of space
| Measure | Two suits | 95% range | Games |
|---|---|---|---|
| Look-ahead player's win rate, all games | 5.7% | 5.0–6.5% | 4,000 |
| Win rate after an empty column before the first deal | 71.4% | 50.0–86.2% | 21 |
| Games where that early empty column happened | 0.5% | 0.3–0.8% | 4,000 |
| Runs completed per game, of 8 | 0.83 | 0.77–0.88 | 4,000 |
| Games with at least 4 runs completed | 6.3% | 5.6–7.1% | 4,000 |
| Moves in a won game, deals included | 154.6 | 152.3–156.8 | 228 wins |
We did not run a separate greedy Spider player, so there is no greedy-versus-look-ahead pair to show here. What we can show is the gap inside our one player's games, and the gap to the published ceiling: Blake and Gent (2026) found even four-suit Spider 98.5% winnable for a solver that sees every card. With two suits, the room for better planning is at least as large.
The early empty column came even more rarely than with one suit (0.5% of games against 1.3%). Mixed-suit builds tie cards down, which makes space harder to create, and that makes it more valuable when you do.
The rules as played on spidersolitaireonline.us
- Cards: 104, in two suits (spades and hearts in our test).
- Layout: ten columns, four of six cards and six of five. Only the bottom card of each is face up.
- Stock: 50 cards, dealt ten at a time, one to each column. Five deals, no reuse.
- Building: any card on one rank higher, in either suit.
- Moving runs: only a run of one suit moves as a group.
- Empty columns: take any card or movable run.
- Completing runs: a King-to-Ace run in one suit is removed automatically.
The game warns you if you try to deal while a column is empty.
What planning looks like with two suits
Choose the same-suit build every time you can
If a spade 6 and a heart 6 can both go on the spade 7, the spade 6 keeps the run movable. Our player's scoring gives far more credit to same-suit links than to mixed ones, and for good reason: a mixed link is a lock you will have to pick later.
Count the cost of each mixed build
Mixed builds are allowed and sometimes necessary to free a card. Before you make one, ask how you will undo it: what card must move, and where will it go? If there is no answer, look for another move.
Spend the early game creating space
Seventy-one percent of games won after an early empty column, against 5.7% overall. Short columns are your best targets. Clear one before your first deal if you can.
Sort before you deal
A deal puts ten new cards on your runs. Before each one, tidy what you can into same-suit order so the new cards interrupt as little as possible.
Expect longer games
Our player's two-suit wins took 154.6 moves, about 37 more than one-suit wins. The extra moves are sorting. Take your time.
Let Undo do your looking ahead
Our player never undoes. Try a line, see what it turns over, and rewind if it tangles the suits.
Playing here
Two-suit Spider is free on spidersolitaireonline.us in any modern browser on computer, tablet or phone. No download, no account, no email. You get large cards with zoom, Hint, unlimited Undo, Restart and Auto Play, drag-and-drop or tap controls, wins, time and moves for the current game, sound on or off, fullscreen and a choice of table colors.
How we ran the study
The spidersolitaireonline.us team ran these simulations in September 2026 on this site's own Spider rules.
- Read the rules from our game's code, as listed above. We assumed you cannot deal with an empty column; the game warns you, but we did not confirm the exact behavior in a browser.
- Wrote the game in Python 3.11, standard library only, in
spider.py; the same program handles one, two and four suits. - Tuned on deals 1 to 30, measured on deals 100,001 to 104,000, each shuffled from a numbered seed so the test can be repeated.
- Used a player that sees what you see. It searches up to 250 positions ahead with the visible cards, treats face-down cards as unknown and never undoes, so its results are floors.
- Logged every game, including whether a column was cleared before the first deal.
- Checked published research. Blake and Gent (2026) do not report two-suit Spider, so nothing outside confirms our 5.7%.
- Put 95% ranges on the figures (Wilson score intervals for rates, normal intervals for averages).
- Named the limits. The 71.4% comes from only 21 games. Deals where an early column appears may also be easier ones, so the figure shows how strongly the two go together rather than proving cause.
Claude, an AI assistant from Anthropic, helped write and review the code and draft this page. Every figure comes from running the code and was checked by the team.
Questions
Why did the win rate fall so far from one suit?
Because builds that are legal can now be immovable. A player that plans only a short way ahead makes mixed builds that later bury cards it needs. Runs completed per game fell from 4.96 to 0.83.
Is 5.7% what I should expect?
No, it is a floor for a player that never undoes. A patient human who builds in suit and uses Undo should do better.
What is the next step?
If you have mastered this, try four suits. For a break, one-suit Spider or Simple Simon. Every game is on the games page, and more is on the blog.
By Admin, spidersolitaireonline.us (Solitairen OOD). Research run September 2026.