Would prefer it as it is.

Easier on my brain to use.

select case mid$(x$,2,1)
case "-":
case "L": (it's check on the long diagonal)
case "S": (it's chek on the short diagonal)
case else: stop: (bug)
end select

It's sort of self documenting.

You can always code an additional module, InCheck2 which does as you suggest if it is easier for you and then let your main module be

Function IsInCheck$(c$)
select case InCheck2(c$)
case 0: IsInCheck$="---"
case 1: IsInCheck$="N--"
...
end select
end function

Mac