Rook is played with four players divided into two teams. Teammates sit across from each other so that play alternates between teams. Each game consists of several rounds until one or both teams reach a pre-determined score (500 by default). The deck is a little different from a standard playing card deck. Instead of spades, hearts, clubs and diamonds, cards have four colors: red, yellow, green, and black numbered 1-14. Additionally, there's one "rook" or "bird" card whose color depends on the situation (more on that later).

The default way of playing is with "1's high", meaning 1 is the highest-ranked card, followed by 14, 13, etc. down to 5. Generally you would play with 2, 3, and 4 removed (and possibly 1 if you're playing 14-high), although you can leave them in if you want to.

Note: Cards are dealt automatically at the start of each round, so this is just to explain what's happening.

Cards are dealt evenly among players, and five cards are placed face-down in the middle of the playing area. These are known as the "kitty" or "nest".

The number of cards you have in your hand will depend on what options you choose, but will range from 9 to 13. Players must keep the cards in their hand a secret from other players (including their teammates).

Each round starts with players taking turns bidding on how many points they think they can win that round. Bidding starts to the dealer's left, and continues clockwise, with each player either passing or increasing the bid in increments of five. The minimum bid is 80 if you're playing 1s high or 70 if you're playing 14s high. The maximum is 180 or 120 respectively.

Once a player passes, they're "out" and can no longer bid. When only one player is left (or bidding reaches the maximum), their bid becomes that team's target score for the round. If they aren't able to collect that many points, their team is "set" and loses however many points they bid. For example, if a player on team A bids 150, and their total at the end of the round is 145, they would have -150 points for the round. The non-bidding team always gets whatever score they ended up with.

After bidding is done, the bidder gets to add the five cards from the kitty to their hand, and discard five cards to keep the total number the same. They can choose any five cards to discard, including any or all of the five they picked up. Note thought, that at the end of the round, whichever team wins the last trick gets any points that were discarded, so take that into account when making your choices. The other players don't get to see what was in the kitty or what's discarded.

The main benefit of winning the bid is the bidder gets to decide the "trump" color (no relation). Any card in the trump color will beat cards from any other color, regardless of their normal rank. You would generally want to choose the color you have the most of in your hand to give yourself the most benefit.

Once the bidder chooses a trump color, they start play by playing any card face up in the center. Play continues clockwise, with players adding a card until they've all played. Whoever has the highest card that either matches the suit of the leading card, or in the trump color wins that trick, along with any points that were played (see below for point cards). If two or more players play the trump suit, the higher card wins. The rook is the highest trump card, so always wins.

Players MUST "follow suit", or play a card with the same color as the leader if possible. If they don't have any cards of the same color, they can play any color, but can only win the trick with a card in the trump suit. The rook card counts as whatever color was chosen for trump, and follows the same rules.

Whichever player wins the trick gets to start the next trick, and play continues until all cards are played.

Points are scored by winning tricks containing point cards. The point cards are the 5, 10, 14, (if playing 1's high) 1 of every color, and the rook card. 5s are with 5 points, 10s and 14s are worth 10 points each, 1s are worth 15 points, and the rook is worth 20 points.

Additionally, whichever team wins the final trick of each round wins whatever points were discarded by the bidder.

After all the points are added up, if the bidding team met or exceeded their bid, they get to keep whatever points they won. If they failed to make their bid (because the non-bidding team took too many points), they lose whatever their bid was. The non-bidding team scores however many points they won, regardless.

Rounds are played, with the dealer moving around clockwise, until at least one team meets the threshold score. By default, this is 500 points, but you can lower it for shorter games.

If both teams reach 500 points, the team that won the bid wins the game.