diff --git a/startup.4th b/startup.4th
index 634d627..3b6e438 100644
--- a/startup.4th
+++ b/startup.4th
@@ -915,12 +915,15 @@ DEFER QUIT
 \ a forward reference to the ENDOF (as with IF ... THEN) above the ENDCASE counter.
 \
 \ Begin by creating a placeholder for the unresolved ENDOF forward references
-: CASE  ( C: -- NULL )  IMMEDIATE
+: CASE  ( C: -- null-orig )  IMMEDIATE
    POSTPONE (ALWAYS) ;
+\ At runtime test the flag on top of the stack; branch to ENDOF if false
+: OF?  ( C: orig-case -- orig-case orig-of ; x flag -- x )  IMMEDIATE
+   POSTPONE (ALWAYS) POSTPONE (ONWARD-IF) POSTPONE DROP ;
 \ At runtime compare the values on the top of the stack; branch to ENDOF if unequal
 \ Keep the first value for the next OF if unequal, otherwise consume both
 : OF  ( C: orign ... orig1 n -- orign ... orig1 n orig-of )  IMMEDIATE
-   POSTPONE OVER POSTPONE = POSTPONE (ALWAYS) POSTPONE (ONWARD-IF) POSTPONE DROP ;
+   POSTPONE OVER POSTPONE = POSTPONE OF? ;
 \ Create a forward branch to ENDCASE and resolve the one from OF
 : ENDOF  ( C: orig-case1 orig-of -- orig-case2 )  IMMEDIATE
    SWAP POSTPONE (ONWARD-AHEAD) SWAP POSTPONE (THEN) ;
@@ -2000,7 +2003,7 @@ NULL 0 TIB-LEFTOVER 2!
          [[ CHAR " ]] OF [[ CHAR " ]] ENDOF
          [[ CHAR ' ]] OF [[ CHAR ' ]] ENDOF
          [[ CHAR \ ]] OF [[ CHAR \ ]] ENDOF
-         TO-LOWER [[ CHAR x ]] OF
+         DUP TO-LOWER [[ CHAR x ]] = OF?
             NEXT-CHAR 16 >DIGIT-BASE 0= "Invalid \\x… escape sequence" ?FAIL
             16 1 ESCAPED-DIGITS
          ENDOF