diff --git a/S1/Echecs/echecs.py b/S1/Echecs/echecs.py
index 6a4ce56..b497551 100755
--- a/S1/Echecs/echecs.py
+++ b/S1/Echecs/echecs.py
@@ -1,5 +1,14 @@
 CASES_COTE = 8
 
+MVT_INCONNU = -42
+MVT_OK = 1
+MVT_ROQUE = 2
+MVT_SELECTION = -1
+MVT_SUR_PLACE = -2
+MVT_SAUT_AMI = -3
+MVT_PION_INC = -4
+MVT_N_AUTORISE = -5
+MVT_OBSTRUCTION = -501
 
 class LogiqueEchecs:
 
@@ -65,74 +74,84 @@ class LogiqueEchecs:
     def mvtPossible(self, x1, y1, x2, y2):
         pion = self.grille[x1][y1]
         if self.aSonTour(pion):
-            if pion > 0:
-                tPion = pion % 10
-                if tPion == 1: # Pion
-                    if x1 == x2 and self.grille[x2][y2] <= 0: # Avance
-                        if self.joueur:
-                            if y2 == y1 - 1:
-                                return [None, True]
-                            elif y1 == 6 and y2 == 4:
-                                return [None, True]
+            if (x1 != x2 or y1 != y2):
+                if not self.aSonTour(self.grille[x2][y2]):
+                    tPion = pion % 10
+                    if tPion == 1: # Pion
+                        if x1 == x2 and self.grille[x2][y2] <= 0: # Avance
+                            if self.joueur:
+                                if y2 == y1 - 1:
+                                    return 1
+                                elif y1 == 6 and y2 == 4:
+                                    return MVT_OK
+                                else:
+                                    return MVT_N_AUTORISE
                             else:
-                                return -4
+                                if y2 == y1 + 1:
+                                    return 1
+                                elif y1 == 1 and y2 == 3:
+                                    return MVT_OK
+                                else:
+                                    return MVT_N_AUTORISE
+                        elif abs(x1-x2) == 1: # Saut
+                            if self.joueur:
+                                if y2 == y1 - 1 and \
+                                self.ePionNoir(self.grille[x2][y2]):
+                                    return MVT_OK
+                                else:
+                                    return MVT_N_AUTORISE
+                            else:
+                                if y2 == y1 + 1 and \
+                                self.ePionBlanc(self.grille[x2][y2]):
+                                    return MVT_OK
+                                else:
+                                    return MVT_N_AUTORISE
                         else:
-                            if y2 == y1 + 1:
-                                return [None, True]
-                            elif y1 == 1 and y2 == 3:
-                                return [None, True]
-                            else:
-                                return -4
-                    elif abs(x1-x2) == 1: # Saut
-                        if self.joueur:
-                            if y2 == y1 - 1 and \
-                            self.ePionNoir(self.grille[x2][y2]):
-                                return [[x2, y2], True] # Saute un noir
-                            else:
-                                return -4
+                            return MVT_N_AUTORISE
+                    elif tPion == 2:
+                        if y1 == y2:
+                            sens = (x2-x1)//abs(x2-x1)
+                            for x in range(x1+sens, x2, sens):
+                                if self.grille[x][y1] > 0:
+                                    return MVT_OBSTRUCTION
+                        elif x1 == x2:
+                            sens = (y2-y1)//abs(y2-y1)
+                            for y in range(y1+sens, y2, sens):
+                                if self.grille[x1][y] > 0:
+                                    return MVT_OBSTRUCTION
                         else:
-                            if y2 == y1 + 1 and \
-                            self.ePionBlanc(self.grille[x2][y2]):
-                                return [[x2, y2], True] # Saute un blanc
-                            else:
-                                return -4
-
+                            return MVT_N_AUTORISE
+                        return MVT_OK
+                    elif tPion == 6: # Roi
+                        if x2 <= x1 + 1 and x2 >= x1 - 1 and y2 <= y1 + 1 and \
+                        y2 >= y1 - 1:
+                                return MVT_OK
+                        else:
+                            return MVT_N_AUTORISE
                     else:
-                        return -4
-                elif tPion == 6:
-                    if x2 <= x1 + 1 and x2 >= x1 - 1 and y2 <= y1 + 1 and \
-                    y2 >= y1 - 1 \
-                            and (x1 != x2 or y1 != y2):
-                        return [None, True]
-                    else:
-                        return -4
+                        return MVT_PION_INC
                 else:
-                    return -3
-
-                return [None, True]
+                    return MVT_SAUT_AMI
             else:
-                return -2
+                return MVT_SUR_PLACE
         else:
-            return -1
+            return MVT_SELECTION
+        return MVT_INCONNU
 
     def mvtsPossibles(self, x1, y1):
         tableau = []
         for x2 in range(0, CASES_COTE):
             for y2 in range(0, CASES_COTE):
-                if type(self.mvtPossible(x1, y1, x2, y2)) is list:
+                if self.mvtPossible(x1, y1, x2, y2) == MVT_OK:
                     tableau.append([x2, y2])
         return tableau
 
     def dPion(self, x1, y1, x2, y2):
         test = self.mvtPossible(x1, y1, x2, y2)
-        if type(test) is list:
-            self.grille[x2][y2] = self.grille[x1][y1]
-            self.grille[x1][y1] = 0
-            if test[1]:
-                self.joueur = not self.joueur
-            return test
-        else:
-            return test
+        if test == MVT_OK:
+            self.grille[x1][y1], self.grille[x2][y2] = 0, self.grille[x1][y1]
+            self.joueur = not self.joueur
+        return test
 
 # GUI
 
@@ -375,9 +394,9 @@ class PlateauTk:
 
     def dPion(self, x1, y1, x2, y2):
         test = self.logique.dPion(x1, y1, x2, y2)
-        if type(test) is list: # Si déplacement possible
-            if type(test[0]) is list: # Si saut → Animation effacement
-                self.animerF(self.grillePions[test[0][0]][test[0][1]])
+        if test == MVT_OK: # Si déplacement possible
+            if self.grillePions[x2][y2]: # Si saut → Animation effacement
+                self.animerF(self.grillePions[x2][y2])
             self.grillePions[x2][y2], self.grillePions[x1][y1] = \
                     self.grillePions[x1][y1], False
             self.animerD((x1 + .5) * COTE_CASE, (y1 + .5) * COTE_CASE, \