diff --git a/src/go.py b/src/go.py
--- a/src/go.py
+++ b/src/go.py
@@ -1,3 +1,8 @@
+import logging as log
+
+from gamerecord import GameRecord
+
+
 EMPTY=0
 BLACK=1
 WHITE=-1
@@ -9,6 +14,8 @@ class Go:
 		self.boardSize=boardSize
 		self.board=[[EMPTY]*boardSize for x in range(boardSize)]
 		self._temp=[[EMPTY]*boardSize for x in range(boardSize)]
+		self.toMove=BLACK
+		self._record=GameRecord()
 
 	## Executes a move.
 	#
@@ -17,6 +24,7 @@ class Go:
 	#  @param color BLACK or WHITE
 	#  @return True on success, False on failure (illegal move)
 	def move(self,color,row,col):
+		if color!=self.toMove: log.warning("move by %s out of order",color)
 		if self.board[row][col]!=EMPTY: return False
 
 		self.board[row][col]=color
@@ -31,8 +39,17 @@ class Go:
 		if not self._floodFill(color,row,col):
 			self.board[row][col]=EMPTY
 			return False
+		self._record.move(color,row,col)
+		self.toMove=-1*color
 		return True
 
+	def transitionMove(self,board):
+		res=transitionMove(self.board,board)
+		if not res: return res
+		(r,c,color)=res
+		return self.move(color,r,c)
+
+
 	## Checks for liberties of a stone at given coordinates.
 	#
 	#  The stone's group is marked with True in self.temp, ready for capture if needed. Recursively called for stone's neighbors.
@@ -57,6 +74,7 @@ class Go:
 			for j in range(self.boardSize):
 				self._temp[i][j]=EMPTY
 
+
 def exportBoard(board):
 	substitutions={EMPTY:".", BLACK:"X", WHITE:"O"}
 	return "\n".join("".join(substitutions.get(x,"?") for x in row) for row in board)
@@ -74,6 +92,24 @@ def isLegalPosition(board):
 	return True
 
 
+def transitionMove(state1,state2):
+	moves=[]
+	for (r,(row1,row2)) in enumerate(zip(state1,state2)):
+		for (c,(item1,item2)) in enumerate(zip(row1,row2)):
+			if item1==EMPTY and item2!=EMPTY:
+				moves.append((r,c,item2))
+
+	if len(moves)==0:
+		log.info("no new stone")
+		return None
+	elif len(moves)==1:
+		log.info("new stone: %s",moves[0])
+		return moves[0]
+	else:
+		log.warning("too many new stones: %s",moves)
+		return False
+
+
 def dfs(stack,board,mask):
 	boardSize=len(board)
 	(r,c)=stack[0]