Texas Hold'em No Limit

environment gif

This environment is part of the classic environments. Please read that page first for general information.

Import from pettingzoo.classic import texas_holdem_no_limit_v6
Actions Discrete
Parallel API Yes
Manual Control No
Agents agents= ['player_0', 'player_1']
Agents 2
Action Shape Discrete(5)
Action Values Discrete(5)
Observation Shape (54,)
Observation Values [0, 100]

Agent Environment Cycle

environment aec diagram

Texas Hold’em No Limit

Texas Hold’em No Limit is a variation of Texas Hold’em where there is no limit on the amount of each raise or the number of raises.

Our implementation wraps RLCard and you can refer to its documentation for additional details. Please cite their work if you use this game in research.



num_players: Sets the number of players in the game. Minimum is 2.

Texas Hold’em is a poker game involving 2 players and a regular 52 cards deck. At the beginning, both players get two cards. After betting, three community cards are shown and another round follows. At any time, a player could fold and the game will end. The winner will receive +1 as a reward and the loser will get -1. This is an implementation of the standard limited version of Texas Hold’m, sometimes referred to as ‘Limit Texas Hold’em’.

Our implementation wraps RLCard and you can refer to its documentation for additional details. Please cite their work if you use this game in research.

Observation Space

The observation is a dictionary which contains an 'obs' element which is the usual RL observation described below, and an 'action_mask' which holds the legal moves, described in the Legal Actions Mask section.

The main observation space is similar to Texas Hold’em. The first 52 entries represent the union of the current player’s hand and the community cards.

Index Description Values
0 - 12 Spades
0: A, 1: 2, …, 12: K
[0, 1]
13 - 25 Hearts
13: A, 14: 2, …, 25: K
[0, 1]
26 - 38 Diamonds
26: A, 27: 2, …, 38: K
[0, 1]
39 - 51 Clubs
39: A, 40: 2, …, 51: K
[0, 1]
52 Number of Chips of player_0 [0, 100]
53 Number of Chips of player_1 [0, 100]

The legal moves available to the current agent are found in the action_mask element of the dictionary observation. The action_mask is a binary vector where each index of the vector represents whether the action is legal or not. The action_mask will be all zeros for any agent except the one whose turn it is. Taking an illegal move ends the game with a reward of -1 for the illegally moving agent and a reward of 0 for all other agents.

Action Space

Action ID Action
0 Fold
1 Check & Call
2 Raise Half Pot
3 Raise Full Pot
4 All In


Winner Loser
+raised chips/2 -raised chips/2

Version History

  • v6: Upgrade to RLCard 1.0.5, fixes to the action space as ACPC (1.12.0)
  • v5: Upgrade to RLCard 1.0.4, fixes to rewards with greater than 2 players (1.11.1)
  • v4: Upgrade to RLCard 1.0.3 (1.11.0)
  • v3: Fixed bug in arbitrary calls to observe() (1.8.0)
  • v2: Bumped RLCard version, bug fixes, legal action mask in observation replaced illegal move list in infos (1.5.0)
  • v1: Bumped RLCard version, fixed observation space, adopted new agent iteration scheme where all agents are iterated over after they are done (1.4.0)
  • v0: Initial versions release (1.0.0)