diff --git a/gib-gab-gob/board.scm b/gib-gab-gob/board.scm
index ada7626..0d58bbe 100644
--- a/gib-gab-gob/board.scm
+++ b/gib-gab-gob/board.scm
@@ -12,12 +12,12 @@
 (define (make-board)
   (make-array #f ggg-size ggg-size))
 
-(define (board-assert-vacant x y)
+(define (board-assert-vacant board x y)
   (define ref (board-ref board x y))
   (if ref (error "That space is already occupied with:" ref) ref))
 
 (define (board-choose! board val x y)
-  (board-assert-vacant)
+  (board-assert-vacant board x y)
   (array-set! board val y x))
 
 (define (board-display board)