A standard deck of 52 playing cards per player
A(low) 2 3 4 5 6 7 8 9 10 J Q K(high)
Players race to get rid of the cards from their "Nerts piles by building them from the ace up onto common foundations
Each player deals a Nerts pile of thirteen cards - twelve cards face down and the thirteenth face up on top. Next to this pile, each player deals four cards face-up, side by side and not overlapping, to begin four work piles. The remainder of each player's cards are held face-down as a stock; these cards will be turned three at a time onto a face up stack, forming the player's waste pile.
Players need to arrange themselves and their tableaus around a common area that all players can access easily. The common area is where the foundations will be placed and built on.
Players play simultaneously as fast as they like, not taking turns, moving cards around their own tableau building on the foundations in the common area. The players' main objective is to eliminate their Nerts piles, by playing cards from them onto their work piles or onto foundations. A player whose Nerts pile is exhausted may call "Nerts!" at which point the game immediately ends. Cards which were in the air being moved from one point to another may complete their move, but no further play is allowed.
It is not necessary to call Nerts! as soon as your Nerts pile is empty. You may choose to carry on playing for a while to try to improve your score further.
Players are only allowed to use one hand at a time to move cards, but may hold their stock in their other hand. Only one card at a time may be moved, except when moving a block of cards from one work pile to another. You can only move cards within your own tableau and into the common area. You cannot touch another player's tableau or take cards out of the common area.
If two or more players try to play to the same foundation at the same time, the first played card (generally the one which ends up lowest in the heap) stays there, and all other players must return the equivalent cards they had just tried to play on that same foundation pile to their previous positions. If there is a tie which cannot be resolved, both cards stay.
You are never forced to play a card if it isn't in your best interest - you can always wait.
A player's four work piles begin with one card each. Work piles are built in descending order, alternating color, overlapping the cards. Thus a red six is placed on a black seven, a black ten on a red jack, and so on. You can move any card in one of your work piles onto another of your own work piles if it fits. When a space results, it may be filled by a card from your Nerts pile, your waste pile or another work pile. The exposed cards of each of the four work piles (i.e. the lowest ranked cards of each pile) are available to be played onto the foundations.
If one of your work piles is empty, you are allowed to save time by placing a card underneath a pile if it ranks one higher than the bottom card and is opposite in colour. For example, if you have a work pile headed by a red jack, and another work pile with nothing in it, and the top card of your Nerts pile is a black queen, it is permissible to take the black queen and slide it under the red jack, rather than first putting the black queen in the space and then moving the whole work pile headed by the red jack on top of it.
Cards from the top of your Nerts pile can be played onto empty spaces in your work piles. If they fit, they can also be played onto one of your existing work piles, or they can be played directly onto a foundation. When you have played the top card of your Nerts pile you can turn the next card of the pile face up. When your Nerts pile becomes empty, you are entitled to call "Nerts!" though you need not do so immediately.
Foundations piles are built in the common area. They are always begun with an ace, and can be built up by playing the next higher card of the same suit (for example the nine of spades on the eight of spades) until the king is reached. Players can always start new foundation piles by placing any available ace in the common area. Other available cards can be played onto an existing foundation where they fit, provided that another player doesn't get there before you. The cards available for playing to foundation piles are: the top card of the Nerts pile, the exposed cards (lowest ranked cards) of each work pile, and the top card of the waste pile. Any player may play onto any foundation. When a foundation is filled up to king, it is turned over and set aside.
You can turn over cards from your stock three at a time and put them face-up onto your waste pile (the waste pile has no cards at the start of play). Be sure to keep the cards in the same order when you do so. The top card of your waste pile may be played to one of your work piles or to a foundation pile if it fits. If there are only one or two cards left in the stock, place them on the waste pile, and then turn the waste pile over to start a new stock; do not pick up the waste pile and place it underneath so that you can deal three cards.
If it happens that all players are stuck (no further legal moves), or no one wishes to play any more cards, then everyone picks up their waste pile to re-form their stock, and then puts the top card of the stock on the bottom. (This happens frequently in a two-player game and rarely with more players.) If you get stuck but others can still play, you have to wait for everyone else to get stuck (or decide they do not want to make any more moves) before you are allowed to transfer your top stock card to the bottom.
When someone calls "Nerts!" play ends and scoring takes place. Each player (team) scores one point for each of their own cards that they managed to play into the common area. To determine this, the foundation piles have to be sorted out according to the owners of the cards - this is why it is necessary that the decks have different backs. All players except the one who called Nerts then subtract two points for every card left in their Nerts pile when play ended. Thus calling Nerts does not guarantee the highest score, but more often than not it does result in a good score.
If all players get so stuck that no card in their stock will play, play stops and the score is calculated as usual. In this case everyone will have to subtract two points for each card that is left in their Nerts pile.
Further deals are played until one or more player's scores reach or pass an agreed target score (usually 100). At this point the player with the highest score wins from each other player in proportion to the difference between their scores.