The GCHQ Christmas Challenge 2023

Maybe we could try this as a joint effort.

https://www.gchq.gov.uk/news/schoolsxmaschallenge2023

Your Mission

Today the #GCHQChristmasChallenge returns, pitting 11 to 18-year-olds against a series of tricky puzzles set by some of our finest minds. And this year is our trickiest Challenge yet! The Challenge is presented in the form of a Christmas card, sent by our Director, Anne Keast-Butler, to partners around the world.

The card, available to download below, contains a series of brainteasers, designed by GCHQ’s own puzzle volunteers, specifically for 11 to 18-year-olds.

Your special festive puzzle mission is to complete the 2023 GCHQ Christmas Challenge by solving the puzzles and uncovering the hidden final message. 

Aspiring spies are asked to solve seven increasingly difficult puzzles and riddles and then use the answers to solve a final challenge. There are some pictures so it's best if you download the Christmas card from the link below. 

You can download the Christmas card puzzles here:

https://www.gchq.gov.uk/files/2023%20GCHQ%20Christmas%20Challenge.pdf

Here is a text version of what's on the card. The text appears as written on the card. All the text in brackets have been inserted by me to explain the pictures.

The GCHQ Christmas Challenge 2023 - Text Version

The seven questions below each have a one-word answer which can follow 'Christmas'. Use the design of the card to help you to put letters from your answers into the grid below to find the final answer. 

1. These clocks show a four-letter word. Can you work it out? 

(A picture shows 4 circular clock faces which are numbered from 1 to 12. They show these times in the following order.)

8 o'clock (with) PM (written below) (has a dark face) 

9 o'clock (with) AM (written below) (has a light face) 

1 o'clock (with) PM (written below) (has a dark face) 

5 o'clock (with) AM (written below) (has a light face) 

2. Can you solve this riddle?

What breaks but can never fall,

can leap but never crawl,

can be seized but never gripped,

often present, never skipped? 

3. We've jumbled up our gift tags! Split them into three groups of three and find a word that links each group.

What word links these three link words? 

(The 9 labels are listed as)

DECLAN BEVERLEY JASMINE

PUDSEY PENNY PITCH

SCARBOROUGH SIRIUS STICKY

[Note - this appears to require some local UK knowledge.]

4. Each letter represents a different digit:

MI x MI = MAA

TI + TI = RA

DO - SO + TI - MI = RE

RE x RE = ?

5. Find the pairs of letters which come next in each sequence:

TH, RD, ND, ??

ET, EL, PM, ?? 

WU, SQ, OM, ??

WR, AP, PI, ??

6. We found a scrap of paper with some bars of music on it which we think are concealing a word. 

Next to the music were some 1s and 0s, and the numbers 16,8,4,2,1. Can you work out the hidden word?

(A picture shows 5 bars of music with no clef or time signature. Each bar has 5 notes. All the notes are written in the spaces and not on the lines. Some are minims [m]- white notes -  and some are crotchets [c] - dark notes. Assuming a treble clef notation of F, A, C, E the notes are as follows:)

(1st bar) A[m] C[m] F[m] A[c] E[c]  

(2nd bar) A[m] E[m] C[m] F[m] A[c]

(3rd bar) C[c] F[m] A[m] C[c] C[m] 

(4th bar) F[m] A[c] E[c] F[c] C[c] 

(5th bar) C[m] F[c] E[c] C[m] F[m] 

7. Look at this message. Can you work it out and find the secret 4-letter word? 

Agklq ldhum qom ndem.

Gembqgax c 4-hmqqmk vdke.

Hddp mumkxvomkm.

Ycxim gq'l umkx diugdsl.

I've already solved most of them, but maybe I'll post this in another thread or on a later page to avoid spoilers.

Update

I've solved it now, including the final challenge. 

I'll post the solutions at some point. But will leave it for others to have a go at. 

The final challenge is here:

There are 7 answers ABCDEFG and you have to put letters into this grid: 

A3 B2 C3 D4 E1 F6 A1 E3

C1 E4 G5 C2 G1 D2 F2 A2 D1 B5 G4 B6 F1

1 is connected with alphabet and is "time"

2. might be "heart"? 

3. Scarborough Fair and Penny Lane are famous songs but which from third song??

4. i would let it to my friend he surely will solve it.

6. might be connected with binary system but i am not good at that and music was my most hated lesson in school because teacher was old witch.

7 some letter swapping stuff but a-z b-y didn't work

5.  no idea

I've just noticed that the solution has now been published on the internet. So I may as well post my answers here and also my method for working them out. 

SPOILER ALERT

The solutions are now posted below.

SPOILER ALERT

Don't scroll down any further if you don't want to read them. 

SPOILER ALERT

The solutions are now posted below.

SPOILER ALERT

1. If you use a 24 hour clock and then the number of the hour corresponds to the letters of the alphabet. 

• 20th letter T
• 9th letter I
• 13th letter M
• 5th letter E

Solution: TIME 

2. Riddles

• DAY break
• Leap DAY
• Seize the DAY
• the present DAY

Solution: DAY

3. I struggled a bit with this one and after I found the first two links I guessed the final link word before getting the last one. 

• BEVERLEY PUDSEY SCARBOROUGH - Are all in Yorkshire
• JASMINE STICKY DECLAN - Rice

With the first 2 answers I guessed the solution was PUDDING.

• SIRIUS PENNY PITCH - Black

So that's Yorkshire Pudding, Rice Pudding and Black Pudding.

Solution: PUDDING

4. Different digits

MI x MI = MAA

• M = 1 is the only possibility
• I = 2 is the only possibility
• 12 x 12 = 144
• A = 4

TI + TI = RA

• Since we know I and A then R = 2 x T
• 1, 2 and 4 are unavailable
• The only solution is R  = 6 and T = 3
• 32 + 32 = 64

DO - SO + TI - MI = RE

• The units simplify to O - O + I - I = E
• So E = 0 
• We already know R = 6 so RE = 60

RE x RE = ?

• 60 x 60 = 3600
• 3600 = TREE

Solution: TREE

5. Pairs of letters

I solved the first one fairly quickly 

• fourTH, thiRD, secoND, firST
• the first 2 letters are ST

It took me a while to solve the 3rd one

• write the alphabet in reverse order skipping every second letter
• xWvU, tSrQ, pOnM, lKjI
• the 5th and 6th letters are KI

So now we have ST..KI.. and then I guessed the answer was (Christmas) STOCKING, which also fits the other 2 pairs of letters. 

• ETELPMOC (Complete) - OC
• WRAPPING - NG

Solution: STOCKING

6. Face the music

As there are 5 notes in each bar I guessed they probably corresponded to 16, 8, 4, 2 and 1

There are only 2 note types minims and crotchets, or white notes and dark notes. So this was probably a binary code and each note was either on or off. 

Using the crotchets as the 1s and the minims as 0s we get this for each bar:

• 2 + 1 = 3
• 1  = 1
• 16 + 2 = 18
• 8 + 4 + 2 + 1 = 15
• 8 + 4 = 12

The maximum value you can get from 5 binary digits is 31 and since there are 26 letters in the alphabet this is a convenient notation for letters. So I tried the simple method first, perhaps A = 1?

• C = 3
• A = 1
• R = 18
• O = 15
• L = 12 

Solution: CAROL

7. Find the secret 4-letter word? 

I started off by guessing from the '4-hmqqmk' that maybe this said '4-letter' word. 

So I filled those 2 words in and then used the same letters in the rest of the puzzle. I then had another part that said:

• .ook e.er.w.ere   

Which seemed to be 'Look everywhere'. 

And then by a gradual process I ended with this:

• First solve the code.
• Identify a 4-letter word. 
• Look everywhere. 
• Maybe it's very obvious.   

Solution: FILM

Final challenge:

The 7 solutions are:

• TIME
• DAY
• PUDDING
• TREE
• STOCKING
• CAROL  
• FILM 

To fit these words into the grid was a process of elimination.

There are 2 uses of the 6th letter and only 2 of the solutions have 6 or more letters, So I started with PUDDING and STOCKING and then gradually filled in the grid. 

Final Solution: YULETIDE FELICITATIONS