diff --git a/buggy.py b/buggy.py
--- a/buggy.py
+++ b/buggy.py
@@ -27,7 +27,7 @@
                     low[row] = 1
                     upper[n - 1 + col - row] = 1
                     lower[row + col] = 1
-                    solve(NULL, board, low, upper, lower, ans, n)
+                    solve(col + 1, board, low, upper, lower, ans, n)
                     low[row] = 0
                     upper[n - 1 + col - row] = 0
                     lower[row + col] = 0
