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A research-focused, Python implementation of Hanabi, including a browser-based user interface
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A platform for the exploration and evaluation of Hanabi AIs


This repository contains an implementation of the card game Hanabi with several different AIs. It can be used to see how current AIs perform, as well as to develop new AIs, including testing them with human cooperators.


Our implementation has two modes of operation: A graphical one, running inside a web-browser, and a command-line option. To use the graphical interface, run:


and open in a web browser. The command line version of the tool is run with

python <players>

where <players> is a space-separated list of AI names. Refer to to see valid names for AIs and general usage. We recommend using the graphical interface for playing the game and general development and restrict using the command line option to run simulations of AI/AI games.


Our implementation was built with extensibility in mind. already contains 8 different AIs, some are implementations of the AIs presented in "Solving Hanabi: Estimating Hands by Opponent's Actions in Cooperative Game with Incomplete Information" (Osawa, Hirotaka, in the proceedings of Workshops at the Twenty-Ninth AAAI Conference on Artificial Intelligence, 2015), while others are our own development, two of which are presented in "An Intentional AI for Hanabi" (Eger, Markus and Martens, Chris and Alfaro Cordoba, Marcela, to appear).

To add another AI, the process consists of two steps:

  1. Subclass Player
  2. Register the new AI

The first step involves implementing the methods get_action and inform. The former is called when it is the AI player's turn, and should return an Action object representing the action the player wants to perform (legal return values are passed as the valid_actions argument), while the latter is called to inform the agent of which actions are performed by the players. The second step adds the AI to the list of AIs the user can choose from in the UI. To do so, add the class to the dictionary ais in, and to the enumeration of available AIs in the html, also in Searching for AIClasses and AIList helps with locating these two locations.

In addition to implementing the methods to play the game, each AI player class can also set the explanation member to a list of lists. This list will be rendered as a table when clicking on the "Explain" button in the user interface. This way it is possible to record and convey information that is helpful with debugging and/or understanding the AI. The SelfIntentionalPlayer uses this to show, among other things, which cards the human cooperator has and which intentions it has for them, what they know about their own hand and the utility of discarding a card. Having this information available during game play can greatly help with improving the AI.


This is the core method of an AI, it is passed 8 parameters:

  • nr: This is the 0-based index of the player that is currently making the decision as an integer.
  • hands: This is a list of list of cards, where each sub-list represents the hand of a single player. Note that since a player can not see their own hand, hands[nr] is the empty list.
  • knowledge: This is a list of player knowledge structures, representing what each player has been hinted about so far in the game. For every player, the knowledge structure is a list of card knowledge structures, one for each card in their hand. These card knowledge structures can then be indexed by a color and a 0-based rank to learn if a player thinks the card could be of this identity or not. For example, knowledge[nr][0][GREEN][1] contains a number greater than 0 if the current player considers it possible that the card at index 0 in their hand is the green 2 (since the rank is 0-based), or 0 otherwise.
  • trash: This is a list of cards already in the trash (after being discarded or played without fitting on the board)
  • played: This is a list of all cards that have been played successfully
  • board: This is a list of cards that are currently on the top of each stack on the board. Empty stacks will have a 0 on top, making it possible to easily check what the next card should be for each color. This is provided as a convenience only, since it could also be calculated from the information contained in played
  • valid_actions: This is a list of valid actions. In particular, it will not contain hint actions if no hint tokens are available.
  • hints: The number of hint tokens left.

The return value of this function should be one of the actions in valid_action. It is not actually enforced that the AI returns one of these objects, it is equally permissible to construct a new action object with valid parameters. Note that the game currently does not enforce that the AI does not cheat by returning a hint action when no hint tokens are available.

Convenience functions

The following functions can be useful when developing a new AI:

  • get_possible takes a card knowledge structure as its argument and returns a list of all identities the card corresponding to the knowledge structure could have.
  • playable takes a card knowledge structure and the board, as represented by the board parameter to get_action and returns True iff the card corresponding to the knowledge structure is guaranteed to be playable
  • discardable takes a card knowledge structure and the board, as represented by the board parameter to get_action and returns True iff the card corresponding to the knowledge structure is guaranteed to be discardable (because it is lower than the next card that would need to be played in its color)
  • potentially_playable and potentially_discardable are the same as playable and discardable, respectively, but return True if the card may be playable/discardable, even if it is not guaranteed
  • update_knowledge takes a player knowledge structure (which is a list of card knowledge structures), and a list of cards used, and removes these cards from the possibilities. Initially, every entry in the knowledge structure contains the number of exemplars of the card corresponding to the entry, and this function decreases that count by one for each card in the list used. The use of this function is to update a player's knowledge by counting which cards have been played or discarded so far, and removing those possibilities from their knowledge base. For example, if a player knows that a card is red, the entries corresponding to the red 1 through 5 will be [3, 2, 2, 2, 1], because there are three red 1s, two of each of the red 2s, 3s and 4s and one red 5. However, if both red 3s have been discarded already, the player can dismiss this possibility. The update_knowledge function is meant to be used to basically subtract the trash and the board from the knowledge to achieve this.

Data Set

Our system can also be used to view replays of games, as well as taking over game play at any point during such a replay, even with a different AI. As an example for the use of this feature, we have obtained a data set, consisting of over 2000 game logs from 240 players, which is available in a separate repository. Simply place the game logs in the log/ directory and they can be opened from the main menu of the UI.


If you use the AIs contained in this project for research purposes, these are the appropriate references:

For the Inner State, Outer State and Self Recognition player:

Osawa, Hirotaka. "Solving Hanabi: Estimating Hands by Opponent's Actions in Cooperative Game with Incomplete Information." Workshops at the Twenty-Ninth AAAI Conference on Artificial Intelligence. 2015.

For the Intentional and Self Intentional player:

Eger, Markus, Martens, Chris and Alfaro Cordoba, Marcela. "An Intentional AI for Hanabi". 2017 IEEE Conference on Computational Intelligence and Games (CIG). IEEE, 2017. pdf

For the timing player:

Eger, Markus and Gruss, Daniel. "Wait a Second: Playing Hanabi without Giving Hints". 14th International Conference on Foundations of Digital Games (FDG), 2019. pdf


Note that Hanabi was designed by Antoine Bauza and is published by Asmodée Éditions, who hold the rights to the game. Our implementation is provided for research purposes only!

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