diff --git a/field.py b/field.py
index 374fda5..f3713a0 100644
--- a/field.py
+++ b/field.py
@@ -152,7 +152,7 @@ class Field():
 
 
     def check_crucial_pos_to_be_free(self):
-        if self.field.state[19][9] == ' ' and self.field.state[19][10] == ' ' and self.field.state[18][9] == ' ' and self.field.state[18][10] == ' ':
+        if self.state[19][9] == ' ' and self.state[19][10] == ' ' and self.state[18][9] == ' ' and self.state[18][10] == ' ':
             return True
         return False