Very interesting approach
char.IsLetter is only viable option if u are aware of ASCII codes of other letters in different alphabets, for instance polish 'ą'.
ah yes, brainfuck.
Clever, wouldn't probably call it best practise as this is specific to an english alphabet (which was ok for this kata)
Recursion is very expensive for this operation.IMHO
smooth. i liked it.
it is lucky that in the first expression has no rows. Otherwise it might not work.
fix your indentation man
I do not want to upset you mate, but it looks like your girl is an alien :D
[C#] (https://www.codewars.com/kumite/5a65f939e6be387c65000059) translation added :)