Eight Off: where our results and the St Andrews study agree

Eight Off is a close relative of FreeCell with two twists: you get eight free cells instead of four, but you must build in suit, and only a King can go into an empty column. It sounds strict, yet it turns out to be one of the most winnable patience games there is. Under this site's rules our solver won 99.89% of 10,000 deals and proved just 0.11% impossible, leaving none undecided.

Eight Off is also one of the games where we could test ourselves properly against the published science. The peer-reviewed study by Charlie Blake and Ian Gent of the University of St Andrews puts the winnable share at 99.8805%. Played under the same one-card-at-a-time rule they used, our solver found 99.80% solved and 0.14% proven impossible. Their figure implies about 0.12% of deals are impossible, which sits inside our margin of error of 0.08% to 0.24%. It is a reassuring match.

Side by side with the published figure

The published impossible share of roughly 0.12% falls inside our range of 0.08% to 0.24%. The site's more generous rule for moving runs rescues only a handful of extra deals: about 0.03%.

More from the deals

• A quick start is usual. In 66% of deals an Ace can go to a foundation straight away, either from the bottom of a column or from one of the pre-filled cells.
• Aces in the cells. In 28% of deals at least one Ace is dealt straight into the four pre-filled cells.
• Short solutions. The first solution our solver found averaged about 35 moves, which is short for a full 52-card game.

The rules as played here

The layout

One pack is dealt face up into eight columns of six cards. That accounts for 48 cards; the remaining four go into four of the eight free cells, so you start with half your cells already occupied.

Moving cards

• Build down in suit: the 9 of spades on the 10 of spades, never on the 10 of clubs.
• Any exposed card can go into an empty free cell.
• Only a King may be placed in an empty column.
• A same-suit run can be moved in one go if you have enough space: on this site, up to the number of empty cells plus empty columns, plus one.

Foundations and winning

Build each suit up from Ace to King on its foundation. Get all 52 cards home to win.

What the figures mean when you play

Losing is almost always a choice

With about one deal in a thousand impossible, a lost game of Eight Off nearly always went wrong somewhere earlier. Undo is the best teacher.

Empty the four pre-filled cells

You begin with four cards in the cells. Getting those out — onto foundations or onto the right suit in the columns — is the first job, because empty cells are what let you move runs.

Plan around the Kings

Only Kings fill empty columns, so an empty column is only useful if a King is ready to move. Clear a column when you can put a King and its run straight into it.

Think in suits

Because building is in suit, each card has exactly one card it can sit on. Before moving, ask where the card you need will come from.

Playing Eight Off on solitaire-free.uk

It is free, it runs in the browser on any computer, tablet or phone, and there is nothing to install and no sign-up. The cards are big and clear with a zoom control; Hint, unlimited Undo, Restart and Auto Play are there whenever you want them; you can drag or tap cards; and your wins, time and moves are shown for the current game. Sound can be switched off, and you can go fullscreen and change the table colour.

How we ran the research, step by step

1. Rules from the site's code. Eight columns of six, eight cells with four pre-filled, building down in suit, Kings only into spaces, and runs of up to empty cells plus empty columns plus one.
2. Two versions. We also coded the stricter one-card-at-a-time rule used in the St Andrews study, so we could compare like with like.
3. Numbered deals. The same 10,000 deals (seeds 1 to 10,000) for both versions, each shuffled from a numbered seed.
4. The solver. Eight Off has no hidden cards, so the solver sees what you see. It searched up to 200,000 positions per deal.
5. Every deal settled. Under the site's rules the solver reached a verdict on all 10,000 deals: won or proven impossible.
6. Checking against St Andrews. Blake and Gent's figure (Journal of Artificial Intelligence Research, 2026) is for one-card moves. Our one-card result agrees with it.
7. Margin of error. A 95% range marks where the true value very probably lies: for the site's rule, 99.80% to 99.94% solved.
8. Limits. 10,000 deals is plenty for the headline but small for a rare event: we saw 11 impossible deals under the site's rules, so the exact impossible share is still a little uncertain.

Behind the numbers: the code

Eight Off lives in freecell2.py, a Python 3.11 module using only the standard library, alongside two-pack FreeCell. The solver is a best-first search that looks at the most promising position next, remembers positions it has already seen so it never repeats work, and plays provably safe cards to the foundations automatically; with same-suit building every foundation move is safe. A shared runner spread the deals across the cores of one machine with Python's multiprocessing; the site-rule run took under a minute and the one-card run about two. Ranges use the Wilson score interval. We used Claude, the AI assistant from Anthropic, to help write and review the solver and draft the page, but every figure comes from running it, and we compared the result with the published study before publishing.

Frequently asked questions

Is Eight Off easier than FreeCell?

Both are winnable almost every time. Eight Off has more cells but stricter building. In our tests its first solutions were shorter, about 35 moves against about 62 for FreeCell.

Why are four cells already full at the start?

Eight columns of six take 48 cards, so the last four go into the cells. It is part of the traditional layout.

Does your result match the published research?

Yes. On the same one-card rule, the published figure implies about 0.12% of deals are impossible; our range for that share is 0.08% to 0.24%.

Why can only a King go in an empty column?

That is the rule in this site's game code. It keeps empty columns precious.

What is similar?

Try FreeCell, Baker's Solitaire (also built in suit) or the bigger FreeCell Two Decks.

By Admin, solitaire-free.uk. Study date: 19 September 2026.