diff --git a/store/src/game.rs b/store/src/game.rs
index 2bf1c64..d1a88ca 100644
--- a/store/src/game.rs
+++ b/store/src/game.rs
@@ -8,7 +8,7 @@ use log::{debug, error};
 
 // use itertools::Itertools;
 use serde::{Deserialize, Serialize};
-use std::collections::HashMap;
+use std::collections::{HashMap, HashSet};
 use std::hash::{Hash, Hasher};
 use std::{fmt, str};
 
@@ -143,6 +143,27 @@ impl GameState {
         game
     }
 
+    pub fn mirror(&self) -> GameState {
+        let mirrored_active_player = if self.active_player_id == 1 { 0 } else { 1 };
+        let mut mirrored_players = HashMap::new();
+        mirrored_players.insert(1, self.players.get(&2).unwrap().mirror());
+        mirrored_players.insert(2, self.players.get(&1).unwrap().mirror());
+        GameState {
+            stage: self.stage,
+            turn_stage: self.turn_stage,
+            board: self.board.mirror(),
+            active_player_id: mirrored_active_player,
+            players: mirrored_players,
+            history: Vec::new(),
+            dice: self.dice,
+            dice_points: self.dice_points,
+            dice_moves: (CheckerMove::default(), CheckerMove::default()),
+            dice_jans: PossibleJans::default(),
+            roll_first: self.roll_first,
+            schools_enabled: self.schools_enabled,
+        }
+    }
+
     fn set_schools_enabled(&mut self, schools_enabled: bool) {
         self.schools_enabled = schools_enabled;
     }
diff --git a/store/src/player.rs b/store/src/player.rs
index eeb5829..fa1e099 100644
--- a/store/src/player.rs
+++ b/store/src/player.rs
@@ -48,6 +48,16 @@ impl Player {
         }
     }
 
+    pub fn mirror(&self) -> Self {
+        let mut player = self.clone();
+        player.color = if self.color == Color::White {
+            Color::Black
+        } else {
+            Color::White
+        };
+        player
+    }
+
     pub fn to_bits_string(&self) -> String {
         format!(
             "{:0>4b}{:0>4b}{:b}{:b}",
diff --git a/store/src/pyengine.rs b/store/src/pyengine.rs
index eed5d93..bd00267 100644
--- a/store/src/pyengine.rs
+++ b/store/src/pyengine.rs
@@ -117,6 +117,10 @@ impl TricTrac {
         self.game_state.to_vec()
     }
 
+    fn get_observation_string(&self, player: PlayerId) -> String {
+        self.__str__()
+    }
+
     /// Afficher l'état du jeu (pour le débogage)
     fn __str__(&self) -> String {
         format!("{}", self.game_state)