1 files changed, 1 insertions, 1 deletions
diff --git a/board.cpp b/board.cpp
index b3820a0..91655dc 100644
--- a/board.cpp
+++ b/board.cpp
@@ -94,7 +94,7 @@ void Board::newEdgeCand(int idx) {
 void Board::removeEdgeCell(int idx) {
 	// cerr << "(removeEdgeCell(" << Idx(idx) << "))" << endl;
 	int pos = inEdgeCells[idx];
-	if (pos != -1) {
+	if (pos != -1 && (bd[idx] != 0 || !checkEdge(idx))) {
 		inEdgeCells[idx] = -1;
 		if ((unsigned)pos < edgeCells.size() - 1) {
 			int val = edgeCells[pos] = edgeCells.back();