Two players only, using a regular 52 card deck. (the older the better, because the cards get abused!!). Shuffle well and divide the cards equally - 26 to each player.
Each player now deals a layout consisting of five stock piles in a row. The first stock pile has 1 card, the second 2 ... the fifth 5. Deal these piles face down and then turn the top card of each stock pile face up (or deal them that way in the first place). That leaves a pile of 11 cards in each player's hand, where they must stay! These are the spit cards, and the players should not look at them.
After both players acknowledge readiness, both shout "spit" while turning over the top card in their hand (their first spit card). These two cards are placed side by side between the players' stock piles. These two cards and the cards that will be played on top of them are the spit piles. The full layout should now look something like this:
The players now play simultaneously as fast as they want. The object is to get rid of all the cards in your stock piles onto the spit piles. Using only one hand, you can either:
play the face up card from the top of one of your stock piles onto either spit pile. To play a card on a spit pile it has to be next in sequence up or down. Suit and color do not matter. Cards can turn the corner - for example on an ace you can play a two or a king;
if one (or more) of your stock piles has its top card face-down, turn the top card of such a pile face-up;
move a face up card from the top of a stock pile into an empty stock pile space if there is one - note that you can never have have more than five stock piles.
Example: In the diagram, player A can play the ace or the three, and then turn up the next card in that stock pile. Playing the 3 is inadvisable as it would allow player B to play the 4. Player B can play the 8 and then it is a race as to whether B manages to play the 9 before A can play 7.
If a position is reached where neither player can play (i.e. none of the exposed stock pile cards can be played to either of the spit piles and it is not possible to turn up another stockpile card after moving cards into spaces if necessary) then both players shout "spit" again, and each turns up their next spit card and places it on top of the spit pile they started. Play then continues as before.
If neither player can play and one player has no spit cards left, then the other player spits alone on only one spit pile. The player can choose either pile, but having chosen, must continue to spit on that pile whenever no play is possible until one player runs out of stock cards. In the event that both players run out of spit cards, the player with the fewer stock cards remaining has choice of spit pile.
When one of the players manages to get rid of all their stock pile cards, both players choose a spit pile by slapping it with their hand - normally both players will try to slap whichever pile they think is smaller. If the two players choose different piles, each player takes the pile they chose; if both choose the same pile, the player who gets there first (i.e. whose hand is underneath) takes the chosen pile and the other player takes the other pile. The player who still has stock cards also picks these up. Both players then shuffle their cards well, and deal new layouts as before from the cards they have, but one player will probably have more spit cards left in hand than the other. When ready, both players shout "spit" and play continues as before.
If one player has fewer than 15 cards, that player will not be able to deal a complete set of stock piles. In this case the player deals the cards into five stock piles as far as they will go, and turns over the top card of each. However, such a player can no longer spit, so there will only be one spit pile, started by the other player.
When playing with only one spit pile, the first player to get rid of their stock cards does not take any cards from the centre; the other player takes the single spit pile and the unplayed stock pile cards. When playing with only one spit pile, if the player with no spit cards in hand also gets rid of their layout cards first, then that player has no cards left at all and has won the game.
Stock pile layout
Some people play with only four stock piles - containing one, two, three and four cards.
Some people deal eleven cards to the centre stock pile, and the other four have just one card each.
In David Shapp's version, the player who first gets rid of all of their stock pile cards has a free choice of which spit pile to take. There is no slapping - the player will simply take the pile they judge to be smaller. The other player then takes the other (probably larger) spit pile and their remaining stock cards and both players deal a new layout. From the feedback I have received, the alternative version in which the spit piles are chosen by slapping is more widespread.
Some play that the cards played on the spit piles must alternate in colour (i.e. on a black 5 you can only play a red 6 or a red 4).
Some play that if on your stock piles you have two cards of equal rank showing (such as two nines), you can move one of these cards on top of the other, thereby exposing a face-down card that can be turned face up, or creating a space. Players and Cards
The Layout
The Play
New Layout
End of the game
Variations
Rules for playing on Spit piles