Jackie, you are either very conversant on the Playfair cipher or else you did what I did and googled Wheatstone. Excuse me, you GoogledŽ Wheatstone. I labored for about a week with the cipher, and ultimately discovered that a small error in my reading of the ciphertext to begin with was holding me back. (What I thought was an "I" was, on closer inspection, an "F.") Of course you must never underestimate the vital importance of guessing the key to the cipher.