← Curifold Puzzle School · 7 minutes ·
A fictional note says UHDG. The sender encoded each plain letter as the letter three places later in the alphabet, wrapping after Z. Recover the message using the supplied key instead of guessing a likely word.
- Find the coded letter
- Read its plain partner
- Re-encode to check
The idea
Encoding goes from the plain row to the coded row. Decoding goes back from the coded letter to its plain partner. Work one letter at a time, then re-encode your answer. This is practice with a given substitution key, not a claim to have broken a secure cipher. Spaces remain unchanged.
Try it yourself
The clues
- The coded message is UHDG.
- Encoding moves three alphabet positions forwards, wrapping after Z.
- Decode by reversing that replacement.
| Row | Letters |
|---|---|
| Plain | A B C D E F G H I J K L M N O P Q R S T U V W X Y Z |
| Coded | D E F G H I J K L M N O P Q R S T U V W X Y Z A B C |
Hint 1
Find U in the coded row; read its plain partner.
Hint 2
The first two decoded letters are R and E. Check the remaining two.
What does UHDG say?
U→R, H→E, D→A, G→D. Re-encoding READ reproduces UHDG.
This shifts the coded letters forwards again rather than decoding them.
H maps to E, not O. Check every letter rather than choosing a familiar word.
Read all responses and explanations
READ
U→R, H→E, D→A, G→D. Re-encoding READ reproduces UHDG.
XKGJ
This shifts the coded letters forwards again rather than decoding them.
ROAD
H maps to E, not O. Check every letter rather than choosing a familiar word.
How is plain Z encoded?
The three forward steps wrap through A, B and C.
W comes from moving backwards; encoding uses the forward direction.
The rule shifts every letter, including Z.
Read all responses and explanations
C
The three forward steps wrap through A, B and C.
W
W comes from moving backwards; encoding uses the forward direction.
Z
The rule shifts every letter, including Z.
Reveal the complete solution
U→R, H→E, D→A, G→D gives READ. R→U, E→H, A→D, D→G is the reverse check. Every coded letter has one plain partner.
Make it your own
Encode MAP and then decode your result without looking at the original. The result should be PDS and then MAP. Test a wraparound letter separately so the end of the alphabet does not catch you out.
Your takeaway
- Copy the coded message
- Pair each coded letter with a plain letter
- Write the decoded word
- Re-encode every letter
- Try another word and a wraparound
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Original fictional educational practice, separate from the puzzles sold in the books. Use the stated rules; there is no speed target or score.
Read the related journal guide · Continue exploring the lessons
Original educational content by Andrew Stinson Books, developed with AI assistance. Our editorial approach.