1 files changed, 1 insertions, 1 deletions
diff --git a/rules.js b/rules.js
index a168fd5..6506e85 100644
--- a/rules.js
+++ b/rules.js
@@ -2701,7 +2701,7 @@ function can_select_op_space(cost) {
 }
 
 function is_selected_op_space(s) {
-	return set_has(game.op.spaces, s)
+	return game.op.spaces && set_has(game.op.spaces, s)
 }
 
 function select_op_space(s, cost) {