Scorpion Solitaire: Spider's one-deck cousin, with a sting
On spidersolitaire.us, Scorpion shares its code with Spider, and it feels like Spider squeezed down to one deck. Cards build in suit, each finished King-to-Ace suit leaves the table by itself, and a gap can only be filled by a King. The twist is borrowed from Yukon: grab any face-up card and everything piled on it comes along, ordered or not.
Scorpion is also one of the least forgiving games we measured. Even a solver that could see every face-down card and the three stock cards proved 67.5% of 3,000 deals impossible on this site's rules. It won 12.9%, and left 19.6% unsettled. Put another way, no amount of skill can win more than roughly a third of Scorpion deals. On our Spider-based difficulty ladder, that sets Scorpion apart from its relatives: four-suit Spider is hard to win, but a Scorpion deal is more often than not impossible to win. Only Baker's Solitaire, at 31.8% on this site's rules, has a similarly low ceiling.
Scorpion on the difficulty ladder
| Game | How we measured it | Deals that can be won |
|---|---|---|
| Scorpion | Our solver that sees every card, 3,000 deals | 12.9% proven; 67.5% proven impossible; so at most 32.5% |
| Spider, 4 suits | Published solver that sees every card | 98.5% |
| Baker's Solitaire (Kings-only spaces) | Our solver, 10,000 deals | 31.8% |
| Simple Simon | Our solver, 3,000 deals | 86.5% proven; 5.2% proven impossible |
Same engine, same building rule, and yet four-suit Spider and Scorpion land at opposite ends of the "winnable" column. The difference is space. Spider has ten columns, two decks and five deals from the stock to reshape the table; Scorpion has seven columns, one deck and a stock of just three cards.
How Scorpion is played here
- Deck: one standard 52-card deck.
- Tableau: seven columns of seven cards. In each of the first four columns, the three cards at the back of the column are face down, twelve hidden cards in all; every other card is face up.
- Stock: the last three cards. One click deals one card to each of the first three columns. You can deal at any time.
- Building: down by one rank in the same suit.
- Moving cards: pick up any face-up card and the whole pile above it travels too, sequence or no sequence. What matters is the card you picked up: it has to land on the next rank up in its own suit.
- Empty columns: Kings only, with whatever sits on them.
- Completing a suit: a full King-to-Ace run in one suit is removed from the table automatically. Remove all four and you win.
What makes Scorpion so unforgiving
Scorpion has a lot of ways to get stuck and very few ways out. Only a same-suit card can receive a move, so each card has exactly one possible destination on the whole table. Only a King can fill a gap. And the stock is three cards, dealt once. If a key card is locked under its own lower suit-mate in a column, there may be no sequence of moves that frees it. Put those constraints together and it is not surprising that our solver proved so many deals impossible.
What the deals tell you
Expect a hidden King
Roughly two deals in three, 65%, begin with a King among the face-down cards.
But they barely change the odds
We compared deals by how many Kings started face down. With two or more hidden, the solver won 14.0%; with none hidden, 12.1%. The difference is small, and in the unexpected direction. Do not give up on a deal just because the Kings look badly placed.
Playing Scorpion well
- Uncover the face-down cards first. The twelve hidden cards in the first four columns are the biggest unknown in the game. Moves that reveal them come before anything else.
- Look for "reverse locks". If a card sits above a lower card of its own suit in the same column (say, the 5 of clubs above the 4 of clubs), that pair can only be separated by moving the upper card somewhere else. Spot these early.
- Use the Yukon-style move. Being able to move a whole unordered stack is your main escape route. Pick up the stack that exposes the most useful card.
- Hold the stock deal back, but not forever. The three stock cards can unblock the first three columns. Deal when those columns need help, not by reflex.
- Accept that some deals are lost. With most deals impossible even in theory, recognizing a dead position and starting over is part of the game. Undo lets you check a line before you abandon it.
Scorpion's toolkit
Since many Scorpion deals cannot be won, Restart and Undo are your testing tools: rewind as far as you like to see whether a different order frees the locked card, and if not, deal again. Hint and Auto Play are there too. Scorpion is free and plays in the browser on any computer, tablet or phone without an account. Use zoom for larger cards, move by drag or tap, and keep an eye on the wins, time and moves counter. Sound, fullscreen and felt color are in settings.
How we tested Scorpion, step by step
The spidersolitaire.us team ran this test on September 19, 2026.
- Traced the rules in our code. Scorpion is a variant of our Spider engine. It lays out seven columns of seven, hides three cards at the back of each of the first four columns (twelve in all), keeps three cards back to be dealt to the first three columns whenever you choose, builds only within a suit, lets any face-up card move with its pile, admits only Kings to gaps and lifts finished suits off the table.
- Rebuilt the game as a program that allows exactly those moves.
- Dealt 3,000 numbered hands, seeds 1 to 3,000.
- Chose a ceiling player. The solver knows the face-down cards and the stock, which no person does, so what it wins is an upper limit. Each deal got up to 200,000 positions.
- Sorted every deal into won, proven impossible or undecided, and noted the face-down Kings.
- Double-checked the "impossible" verdicts. A separate brute-force program, written independently of the solver, confirmed the impossible verdicts on the deals we tested with it. Scorpion is not in the main published study we check against, Blake and Gent (2026), so there is no outside figure to compare with.
- Worked out the margin of error. For 12.9% won the 95% range is 11.7% to 14.1%; for 67.5% impossible, 65.8% to 69.2%.
- Named the limits. The solver sees hidden cards, so 12.9%–32.5% is an upper limit for a real player.
The Scorpion solver in brief
Our Scorpion solver is one half of spiderlike.py (Simple Simon is the other), written in Python 3.11 with standard-library code only. It holds a queue of positions ranked by promise, always takes the best, and logs every position so it is never examined twice. On 19 processes the 3,000 deals needed around 48 minutes. The ranges quoted are Wilson score 95% intervals. Claude, an AI assistant from Anthropic, helped us write, review and describe the solver; what it found is the solver's work, not the AI's.
Scorpion questions
Is Scorpion related to Spider?
Closely. It runs on the same engine, builds in suit and removes completed suits automatically. The unordered group move comes from Yukon.
Must a moved pile be in sequence?
No. Only the card you pick up has to fit; whatever sits on it can be in any order.
Is there a right moment for the three stock cards?
Only one: when the first three columns need a new card. You can deal them whenever you like, but it happens once.
Why do I lose so often?
Because most deals cannot be won. Even seeing every card, our solver proved 67.5% impossible.
What is a gentler game in the same family?
Simple Simon keeps the Spider feel with every card face up, and one-suit Spider is the easiest rung of all.
By Admin, spidersolitaire.us (Solitairen OOD). Research run September 2026.