diff --git a/src/sudoku.s b/src/sudoku.s
index d9e35af..fd61148 100644
--- a/src/sudoku.s
+++ b/src/sudoku.s
@@ -119,6 +119,8 @@ PFIELN: .IOT  CHTTYO,[^M]              ;Print a carriage return.
 PFIENO: .IOT  CHTTYO,[040]             ;Print a space.
         ILDB  B,X                      ;Load the next field.
         ADDI  B,060                    ;Convert number into char.
+        CAIN  B,060                    ;If B is not '0', skip
+        MOVEI B,040                    ;Replace '0' with a space character.   
         .IOT  CHTTYO,B                 ;Print the number.
         .IOT  CHTTYO,[040]             ;Print a space
         .IOT  CHTTYO,[174]             ;Print a '|' symbol