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Logic Puzzles
“Uncle Bob”

Each month in 2020 I plan to feature a different type of logic puzzle. This month it’s…

More Decoding Puzzles

1. Cryptogrmas

Ordinary cryptograms use a simple substitution of one letter for another consistently throughout a puzzle. The puzzle appears in ciphertext, it is encoded. If V is the coded form of letter E, then every V is an E in the puzzle. You solve the puzzle by uncovering the plaintext, the message in English. Proper names are usually marked with an asterisk, for example *ATWUAE might be code for *ROBERT.

Here are the average counts out of every 100 letters for each plaintext letter.

Here is a word that every codebreaker knows by heart: ETAOINSHRDLU. The word has no meaning in English, but if you compare it to the frequency table, you’ll see that this strange word lists, in order, the most commonly used English letters. Keep this word handy. A pronunciation might help you to remember it: eh-tay-oh-in-shrd-lu.

Martin Gardner, in a chapter entitled "How to Break Substitution Ciphers" gives facts about English which help us solve cryptograms. Here are some:

• Single letter words are almost always A or I.
• Frequent two-letter words are OF, TO and IN. Look also for ON, OR, AT and IS.
• We expect to see THE and AND more than other 3-letter words.
• Common double letters are LL, EE, SS, OO, TT and FF, among others. You'll be able to spot them as repeating cipher letters.
• The easiest 4-letter word to spot is THAT, especially if you have found THE.
(Gardner. Codes, Ciphers and Secret Writing. p. 35, 36)

Your puzzle is a poem – one with a subject we all can appreciate amidst this covid-19 pandemic.

Get a print friendly pdf here.


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