Simple Simon: Spider's rules, one open deck
Take Spider, cut the 104 cards down to one 52-card deck, turn every card face up and throw away the stock. That is Simple Simon. Ten stepped columns hold the whole deck from the start, you may build any card on the next rank up, and only same-suit runs move as a block. With nothing hidden and nothing still to come, it sits next to our home game, FreeCell Two Decks, as one of the site's open-information games, just with half the cards.
A best-first solver on this site's rules found a winning line in 86.5% of 3,000 deals (95% range 85.3%–87.7%), proved 5.2% impossible (4.4%–6.0%) and left 8.3% undecided (7.4%–9.3%). FreeCell Two Decks, with 104 open cards, was solved in 88.0% of 400 deals (84.4%–90.8%) with none proven impossible. Those are different games with different budgets, so read them side by side, not as a controlled one-deck-vs-two test.
At a glance: one open deck on the Spider engine
| Measure | Result | 95% range | Deals |
|---|---|---|---|
| Simple Simon (52 cards): solved | 86.5% | 85.3–87.7% | 3,000 |
| Simple Simon: proven impossible | 5.2% | 4.4–6.0% | 3,000 |
| Simple Simon: undecided | 8.3% | 7.4–9.3% | 3,000 |
| Same-suit links already in place at the deal | 0.76 | 0.73–0.79 | 3,000 |
| FreeCell Two Decks (104 cards): solved | 88.0% | 84.4–90.8% | 400 |
| FreeCell Two Decks: proven impossible | 0.0% | 0.0–1.0% | 400 |
Every card is visible in both games, so the solver's wins are real wins on these rules, not ceilings that need hidden knowledge.
Half of Spider's deck, all of it on show
Spider's 104 cards come as eight full suits, so there are two of every card and two chances to complete each suit. Simple Simon has four suits and one of each card. A 6 of hearts has one same-suit 7 to join; if that 7 is badly placed, the 6 waits. On the other hand, you can see every card from move one, which Spider never gives you. We have no solver figure for Spider on this site's rules and no two-deck Simple Simon, so we can't put a number on the trade.
Simple Simon rules on this site
- Deck: one 52-card deck, every card face up.
- Tableau: ten columns: three of eight, then seven, six, five and so on down to one.
- Stock: none.
- Building: any card on the next rank up, any suit.
- Moving: a same-suit descending run moves as a block, any length; mixed runs must be taken apart.
- Empty columns: any card or same-suit run.
- Suits: a full King-to-Ace suit is removed automatically; clear all four to win.
Playing one visible deck
Almost all order is yours to build
A fresh deal has on average 0.76 same-suit links. Each one you add is progress; any-suit builds are only temporary parking.
Clear a short column first
The right-hand columns hold one, two and three cards. Plan which to empty first, then keep that gap working.
One suit at a time
With only four suits, finishing one removes a quarter of the deck. Pick the least buried suit and drive it home.
Each card has one same-suit partner
Before burying a card, check it isn't the only same-suit link something else needs.
Rewind without cost
Nothing is hidden, so Undo is pure planning. If several different plans all stall, the deal may be one of the 5.2%.
Playing on freecell-two-decks.com
Simple Simon is free in any current browser on computer, tablet or phone, with no account. Hint, unlimited Undo, Restart and Auto Play are included, with zoom, fullscreen, drag or tap moves, a counter for wins, time and moves, and sound and table-color settings.
How the figures were made
The freecell-two-decks.com team ran this test in September 2026 on this site's Simple Simon rules.
- Rules from the code: every card face up in ten stepped columns, any-suit building, same-suit runs moving with no length cap, any card into a gap, finished suits removed.
- A Python 3.11 program, standard library only, shared with Scorpion.
- 3,000 numbered deals, seeds 1 to 3,000.
- A best-first solver with up to 200,000 positions per deal.
- Published comparison: Blake and Gent (2026) estimate 97.450% winnable, implying at most about 2.55% impossible. We proved 5.2% impossible. A separate brute-force program confirmed six of our impossible deals, one of which has no legal first move. We have not found the cause of the difference, so treat our Simple Simon figures as provisional.
- No two-deck Simple Simon was simulated.
- 95% ranges: Wilson score intervals, normal interval for the average.
Claude, an AI assistant by Anthropic, helped write and review the code and draft this page. Every figure comes from running the code, and the team checked them.
Simple Simon questions
Is every deal winnable?
No: 5.2% were proven impossible. Most of the rest come down to planning.
How is it different from Spider?
One deck instead of two, no stock, nothing face down. Try Spider for the 104-card game.
Can a mixed run move?
No, only same-suit runs move as a block.
What next?
Scorpion is a harsher one-deck cousin; FreeCell Two Decks gives you 104 open cards. All games are on the games page.
By Admin, freecell-two-decks.com (Forty Media). Research run September 2026.