Chaos;Jan has six different card types.
They are Action, Character, Hyper, Modifier, Negate, and Stock.
Each card type has specific timing rules for when they can be played.
A card's card type can be seen at the top of the top of the card.

• 1.1: Action cards are cards that cause a short-term effect and then is discarded. These cards can be played during any player's turn.
• 1.1a: When an Action card is put into play, its effect occurs and then is discarded.
• 1.1b: If an Action card is discarded or returned to a players hand from play before its effect occurs, its effect does not occur.
• 1.1c: Action cards can only be played when a player has priority. See the priority rule for more. Note that a player does not need to be the active player to play an Action card.
• 1.1d: After a player plays an Action card, they pass priority. This means that after a player plays an Action, another player may play a card before the first player can play another card.
• 1.1e: Some Action cards allow them to be played as a part of declaring riichi. This is a special case where the player does not need priority to play it.
• 1.1e.1: Playing an Action card this way creates a round of priority if the riichi is valid. Since the active player has played an Action card, they pass priority immediatly.
• 1.1f: Some Action cards have restrictions that limit when a player can play that card.

• 1.2: Character cards are cards chosen by each player before the game begins that determines that player's color and Hyper effect (see rule 1.3).
• 1.2a: Character cards are chosen before the first round.
• 1.2b: Character cards have a color indicated at the top, under the name.
• 1.2c: Character cards have a hyper effect. This is the effect that will occur when a player plays a Hyper card.
• 1.2d: Non-Hyper, non-Negate cards have bonus effects underneath their normal effects. This is marked with a symbol of the corresponding color followed by a colon.
• 1.2d.1: These symbols are 中, 發, and 白 for red, green, and white, respectively.
• 1.2d.2: This symbol means "If your Character has the same color as this card, then also do: ..."

• 1.3: Hyper cards are cards that have a powerful effect based on a player's Character card.
• 1.3a: The effect of a Hyper card is on the Character card of the player who played it.
• 1.3b: Some Hyper effects are also Stock effects. These effects follow the rules of Stock cards. See rule 1.6.
• 1.3c: Hyper cards can only be played when a player has priority, is the active player, and before that player draws a tile. See the priority rule.
• 1.3d: Some Hyper effects allow the player to play that Hyper when they are not the active player.
• 1.3d.1: If a Hyper effect allows the play to play it "at any time", that effect follows the rules of Action cards. See rule 1.1.
• 1.3e: Hyper cards cannot be negated.

• 1.4: Modifier cards are cards that alter the rules of the hand for each player.
• 1.4a: Modifier cards start in a separate deck called the "Modifier Deck".
• 1.4b: Players do not play Modifiers
• 1.4b.1: After a wind rotation or at the start of the game, a Modifier is drawn from the Modifier Deck and is put into play.
• 1.4b.2: Modifiers cannot be negated by players.
• 1.4c: A Modifier's effect lasts until it is replaced by another Modifier.
• 1.4c.1: Only one Modifier can be in play at a time.
• 1.4c.2: If a Modifier would be put into play, all Modifier cards in play are discarded, then that Modifier is put into play.
• 1.4d: A Modifier's color bonus effect applies to each player whose Character matches that color.
• 1.4e: If a Modifier's effect refers to "You", that effect applies to each player individually. Each player should treat that effect as though it were a Stock effect played by them.

• 1.5: Negate cards are cards that can prevent a card's effect from occuring.
• 1.5a: Negate cards use the sub-priority system.
• 1.5a.1: A Negate can only be played when a player has sub-priority. See rule P.7.
• 1.5a.2: After a player plays a Negate card, they pass sub-priority.
• 1.5a.3: Negate cards can be played at the same time as another card.
• 1.5b: Each Negate card has the effect: "Negate the last played card before its effect occurs."
• 1.5c: To negate a card means to discard that card before any of its effect can occur.
• 1.5d: A Negate can be played in response to another Negate. When this happens, apply the effects of the most recently played card first. For example, East plays an Action, South plays a Negate, then East plays a Negate. East's Negate will discard South's Negate before it can discard the Action, letting the Action's effect apply normally.

• 1.6: Stock cards are cards that have a lasting effect.
• 1.6a: Stock cards can only be played when a player has priority, is the active player, and before that player draws. See the priority rule.
• 1.6b: While a Stock effect is active, that card that caused that effect remains in play for as long as the effect is active.
• 1.6b.1: Once the effect is no longer active, the card that caused that effect is discarded.
• 1.6c: Most Stock effects have an "active time" phrase on them. For example, "Until the end of this hand," and, "The next time you deal in," are both active time phrases.
• 1.6c.1: Active time phrases dictate how long the Stock effect should remain active.
• 1.6c.2: If a Stock effect does not have an active time phrase, it remains active until the effect is no longer applicable. For example, Futuresight's effect can only apply up until a certain tile is discarded or until two of a certain tile are revealed from a hand. Once either of these conditions are met, Futuresight is discarded.

• P.1: At the beginning of the active player's turn (before they draw) and after that player draws a tile, that player receives priority.
• P.2: While a player has priority, they may choose to either play a card or pass priority.
• P.3: Priority is passed in turn order. For example, if East is the active player, they will pass priority to South, who will pass to West, et cetera.
• P.4: When priority is passed, any card played whose effects have not yet occured applies their effects.
• P.5: Priority is passed until each player has received priority but no cards were played since the last time they've received priority.
• P.6: Once priority passing has stopped, no one has priority, and the next step in the Mahjong game may happen.
• P.7: For Negate cards, there is another round of priority before main priority is passed. This is called "sub-priority".
• P.7a: Sub-priority works identically to main priority.
• P.7b: When a player plays a card, that player receives sub-priority.
• P.7c: Once sub-priority passing has stopped, no one has sub-priority, and main priority is passed.
• P.7d: If main priority tries to get passed before the round of sub-priority finishes, it waits for the round of sub-priority to finish first.