- Not to be confused with Reactor 1.0 or Reactor 2.0
If anything in this doc is unclear, please just ask on the Hanabi Central discord or edit it yourself!
In ReactorZero, the conventions prioritize simplicity and clarity over efficiency. Knowledge of Reactor 1.0 or Referential Sieve not required!
ReactorZero is intended to be both a teaching tool for Reactor 1.0 and 2.0 but also an experiment to see how many fewer conventions Reactor can have.
We first lay out the conventions for 3-player games then discuss conventions that change in 4-player games.
In ReactorZero, there are two types of clues: stable and reactive.
We name the player taking an action Alice, and the subsequent players Bob, Cathy (and Donald/Emily in larger games).
If Alice gives Bob a clue, it is a stable clue.
Clue type | Meaning |
---|---|
Color (touching new cards) | Play leftmost newly touched card |
Rank (touching new cards) | If the rightmost unclued card is touched, the clue recipient is locked; if not, they can discard the first unclued card to the right of the leftmost newly touched card |
Either (touching no new cards) | Play leftmost touched card |
A locked player may not discard any card until they receive a safe action.
An unlocked player, without a known or signaled action (play or discard), may discard their leftmost unclued card (their "chop") instead of giving a clue.
ReactorZero does not have special stalling conventions. In a "stalling situation" without reactive clues, you can give a stable clue. (It's also a stall if the card that was called to play is not immediately playable or if the card would be the same as a card with full empathy in the player's hand. The clue has no meaning beyond the information it provided to the hand.)
When Alice is cluing Cathy, the clue is reactive.
It gets an action from Bob (the reactor) followed by an action from Cathy (the receiver). When Bob takes that action, we say that Bob reacts to the reactive clue.
The type of action (discard or play) in both hand is determined by the type of clue:
Clue type | Meaning |
---|---|
color | odd number of plays (1 discard + 1 play or 1 play + 1 discard) |
rank | even number of plays (2 plays or rarely 2 discards) |
The total of a reactive rank clue corresponds to the numerical value of the rank clue. (E.g. If the clue was a rank 3 clue, the clue total is 3.)
The total of a reactive color clue depends is the position of the color in the cluing palette of the interface. (The leftmost color gives a clue total of 1, the 2nd-leftmost color has clue total 2, et cetera.)
The totals of reactive color clues may be changed through pre-game agreement. For example, in a variant with two possible color clues, color=34 would mean the leftmost has value 3 and the 2nd-leftmost has value 4.
The actions (play or discard) will come from one of Bob's slots and one of Cathy's slots while respecting the equation
Clue total = Bob's slot + Cathy's slot (modulo 5)
Assuming Cathy's targeted action is to play slot 4 and Alice gives a color clue to Cathy with clue total 1, Bob discards slot 2 because 2+4=6=1 (modulo 5).
In order for Bob to know which action he should take, Alice and Bob need to agree on which action Cathy should take. This is achieved by the following targeting priority.
Targeting priority in Cathy's hand:
When targeting, the status of cards (obviously playable, one-away, trash, ...) is determined before the reactive clue is given.
(A card is obviously playable if it is play-signaled or if its empathy only contains immediately playable cards globally.)
When Cathy is signaled a play, the targeted card in Cathy's hand must be immediately playable after Bob reacts.
When targeting, the leftmost copy of a duplicated card in the same hand is considered trash.
If the clue does not work (lead to an immediate bomb or make a critical card discard), the target is moved to the next target in the priority list.
Good touched cards do not play on their own unless absolutely necessary to get maximum score.
Bob may chose to delay reacting to a reactive clue, in this case the reactive clue is semi-revoked:
In a game with 4 players or more, the same reasoning is applied when a reactor delays a reactive clue, the signal to later players is lost.
Cathy must ignore the entire reaction and proceed as if she was locked for that turn. (The same principle applies if a reactor bombs in a game with 4 or more players.)
As in a 3-player game, Alice's clues to Bob are stable.
As in a 3-player game, Alice's clues to Cathy are reactive. Since each hand contains 4 cards in a 4-player game, the equation involving the clue total is changed to
Clue total = Bob's slot + Cathy's slot (modulo 4).
All clues to Donald are double reactive. They get an action from Bob (the first reactor) followed by an action from Cathy (the second reactor) followed by action from Donald (the reciever).
Clue type | Meaning |
---|---|
color | odd number of plays (3 plays or rarely 1 play) |
rank | even number of plays (2 plays or very rarely 0 plays) |
Clue total = Bob's slot + Cathy's slot + Donald's slot (modulo 4)
Targeting priority in Donald's hand:
The target in Donald's hand is fixed, then the target in Cathy's hand is determined, then Bob computes his slot.
6-player games follow the same guildlines in principle.
Clues to Bob, Cathy and Donald have the same meaning as in a 4-player game.
All clues to Emily are triple reactive. They get an action from Bob (the first reactor) followed by an action from Cathy (the second reactor) followed by action from Donald (the third reactor), followed by an action by Emily (the reciever).
Clue type | Meaning |
---|---|
color | odd number of plays (3 plays or very rarely 1 play) |
rank | even number of plays (4 plays or rarely 2 plays or extremely rarely 0 plays) |
Clue total = Bob's slot + Cathy's slot + Donald's slot + Emily's slot (modulo 4)
Targeting priority in Emily's hand:
The target in Emily's hand is fixed, then the target in Donald's hand is determined, then the target in Cathy's hand is determined then Bob computes his slot.