diff --git a/src/go/engine.py b/src/go/engine.py
--- a/src/go/engine.py
+++ b/src/go/engine.py
@@ -8,7 +8,6 @@ def transitionSequence(state1, state2, d
 class SpecGo(core.Go):
 	def __init__(self):
 		super().__init__()
-		self._diff=[]
 
 	def load(self,state):
 		for (r,row) in enumerate(state):
@@ -16,27 +15,49 @@ class SpecGo(core.Go):
 				self.board[r][c]=x
 
 	def listRelevantMoves(self,diff):
-		res=([],[])
+		"""There can be 3 different changes in the diff: additions, deletions and replacements.
+		Additions can be taken as relevant right away.
+		Deletions and replacements had to be captured, so we add their liberties.
+		Also any non-missing stones of partially deleted (or replaced) groups had to be replayed, so add them too.
+		Needs to handle: Take n, return 1. Snapback.
+		There's no end to what could be theoretically relevant, but such sequences are long and we will pretend they won't happen."""
+		res=(set(),set())
 		for d in diff:
 			(r,c,action,color)=d
-			colorKey=(1-color)<<1
-			if action!="-":
+			colorKey=(1-color)<<1 # {-1,1}->{1,0}
+			if action!="-" and (r,c) not in res[colorKey]:
 				res[colorKey].append((r,c))
-			if action!="+":
+			# this is rather sloppy but correct. the time will show if it is effective enough
+			if action!="+" and (r,c) not in res[colorKey] and (r,c) not in res[1-colorKey]:
 				self._helper.clear()
-				self._helper.floodFill(color,r,c)
-				res[colorKey].extend(self._helper.getLiberties())
+				self._helper.floodFill(color if action=="-" else 1-color, r, c)
+				res[colorKey].union(self._helper.getContinuousArea())
+				for (ri,ci) in self._helper.getContinuousArea():
+					res[colorKey].add((ri,ci))
+					res[1-colorKey].add((ri,ci))
+					if ri>0:
+						res[colorKey].add((ri-1,ci))
+						res[1-colorKey].add((ri-1,ci))
+					if ri<self.boardSize:
+						res[colorKey].add((ri+1,ci))
+						res[1-colorKey].add((ri+1,ci))
+					if ci>0:
+						res[colorKey].add((ri,ci-1))
+						res[1-colorKey].add((ri,ci-1))
+					if ci<self.boardSize:
+						res[colorKey].add((ri,ci+1))
+						res[1-colorKey].add((ri,ci+1))
 		return res
 
 
 class Engine:
 	def __init__(self):
 		self._g=SpecGo()
-		self._diff=[]
+		self._moveList=(set(),set())
 
 	def load(self,state1,diff):
 		self._g.load(state1)
-		self._diff=diff
+		self._moveList=self._g.listRelevantMoves(diff)
 
 	def iterativelyDeepen(self,state2):
 		for i in range(1,10):
@@ -45,13 +66,13 @@ class Engine:
 
 	def dfs(self,state2,limit):
 		g=self._g
-		for m in g.listRelevantMoves():
-			g.doMove(m)
-			if g.board==state2: return m
+		for (r,c) in self._moveList[g.toMove]:
+			g.doMove(g.toMove,r,c)
+			if g.board==state2: return [(r,c)]
 			if limit>1:
 				seq=self.dfs(state2,limit-1)
 				if seq:
-					seq.append(m)
+					seq.append((r,c))
 					return seq
 			g.undoMove(m)
 		return False