Spider solitaire rules

Dealing the cards

Shuffle two standard decks together without jokers. Deal ten columns: the first four get six cards each and the other six get five, all face down except the top card of each column. That uses 54 cards. The other 50 go face down as the stock, enough for five more deals of ten.

Rule books differ slightly here. Bicycle's version deals five cards to every column (50 on the table, 54 in the stock). The 54/50 split above is the one most computer versions use; both play the same way.

1, 2 or 4 suits

The suit count is the difficulty setting, and it only changes which 104 cards are in play.

• 1 suit: all 104 cards are spades (eight sets of Ace to King). Every run you build is already in suit, so the game is mostly about ordering. This is the beginner game.
• 2 suits: four sets of spades and four sets of hearts. Now a black 8 on a red 9 is legal but blocks that run from moving.
• 4 suits: two ordinary decks. The hardest and the one you play with real cards: making the 1 or 2 suit decks at home would take the spades (and hearts) from several decks.

Moving cards

Any face-up card at the end of a column can go onto a card one rank higher in another column, of any suit. A 7 of hearts may sit on an 8 of clubs. A run of cards can move as a unit only if every card in it is the same suit and in order: 9-8-7 of spades can move together, but 9 of spades, 8 of hearts, 7 of spades cannot. You may also split a same-suit run and move just its lower part.

When the last face-up card leaves a column, turn up the face-down card below it. An empty column takes any card or any movable run, not only a King, which makes empty columns the most valuable thing in the game.

When a column holds a complete King-to-Ace run in one suit, lift those 13 cards off and set them aside. Most apps do this for you; with real cards it is up to you, and leaving a finished run in place for a while is allowed.

Dealing from the stock

When you run out of useful moves, deal ten cards from the stock, one face up on the end of each column. First fill every empty column; the rules do not allow a deal over an empty space. There are five deals in all. After the last one, you finish with what is on the table.

You win when all eight runs are complete.

How often can Spider be won?

In theory, nearly always. Charlie Blake and Ian Gent's solver study (arXiv 1906.12314) put the standard two-deck game at about 98.5% winnable (plus or minus 1.5%), but that is for a player who knows where every face-down card is.

Real results are much lower and depend heavily on the suit count. On Solitaire Bliss, which publishes its own players' records, the win rates are about 60% with 1 suit, 20% with 2 suits and 8% with 4 suits. So with real cards (4 suits) expect to lose most deals, and treat a win as a real achievement.

Strategy

1. Empty a column as early as you can. An empty column takes anything, so it works as a parking space that lets you untangle mixed runs. With 4 suits, an open column is often the only way to swap two off-suit cards back into order.
2. Build in suit whenever you have a choice. If both a 9 of spades and a 9 of hearts can take your 8 of spades, choose the spade. An off-suit stack is a dead end you will have to take apart later.
3. Go after the tall columns. The first four columns hide five cards each. Clearing one of them uncovers more new cards than clearing a short column.
4. Get ready before you deal. A deal drops a card on every column and can bury a run you were about to finish. Before you deal, finish any in-suit moves, and use an empty column to sort, then fill it with the least useful card.
5. Put Kings away carefully. A King can only ever move to an empty column, so a King that lands on top of a column you hoped to clear stays there. Prefer to move a King into a space only when it brings a run with it.