These puzzles have been set by fans of the Cipher Challenge, and we are using a variation on the Enigma Rotor Scale pioneered at GCHQ to give you some idea how hard they might be. Sometimes your conscious mind need a rest from codebreaking and we think this is a good way to distract you while your brain gets on with the important work of breaking them in the background. We don’t think there will be anything harder than a 4 here, but you never know until you try … https://www.gchq.gov.uk/information/enigma-rotor-scale

- Very easy. Should be quickly solvable.
- Not too hard but not immediately obvious. You probably need to make a cup of tea for this one. Coffee works too.
- Getting a bit hard now. Tea drinking will help, but a bit of pacing around the room is probably in order as well.
- Something of a meaty challenge and probably one that you might need help with. There is no shame in collaborating with other people to solve it.

- BOSS PUZZLE CHALLENGE 7 – open until Sunday 6th Dec 9am
OUR RESIDENT GUEST PUZZLEMASTER IS TLW, THE LETTER WRIGGLER, whose identity, like those of all our officers and agents, is a closely guarded secret.

TLW first became interested in ciphers after reading Simon Singh’s The Code Book in 1998. He found the now NCC web page way back in the early 2000’s and has enjoyed every years session since, but until 2019 he remained a ‘lurker’ never registering (because it was for schools only and did not think he should).

His current interests and hobbies include electronics, recreational maths & puzzles, number theory and ciphers, and learning to play his Yamaha Tyros keyboard.

In the completed puzzle the numbers 0 through 9 appear in each of the top six rows of the grid so that they give the column sums at the bottom and

*no number appears in twice in adjacent cells*, including diagonal adjacency. - BOSS PUZZLE Solution 6
OUR RESIDENT GUEST PUZZLEMASTER IS RODERICK KIMBALL, the fiend behind Enigami. Roderick was born in BC, making him either ridiculously old, or simply Canadian. In his youth, Roderick was sometimes spotted on the slow end of a soccer pitch but more often on the fast end of a chess board. (Surely you’ve heard of the notorious Kimball maneuver, in which one opens a chess match by flipping the king’s pawn into the air such that it lands, butter side up, on the king’s fourth rank.) Roderick has created puzzles for the National Museum of Mathematics, Games Magazine, Reader’s Digest Canada, NPR’s Ask Me Another and for his own amusement. In the other half of his life, Roderick has toured the world juggling with the Flying Karamazov Brothers. He also recently returned from Kenya, where he was sent by Engineers Without Borders to help folks with improving their water supply. He is proud to say that his ancestry includes two very great grandmothers who were executed as witches and he once made bottled water come out Rosie O’Donnell’s nose.

Arrange the numbers 1 through 9 in the grid so that all of the conditions in the puzzle are satisfied. Every number is used once. The rules are

*The 8 is between the 1 and the 5 on a straight line.There is a number in a corner that is the sum of the other two numbers in its row, column, and diagonal.The numbers in the left column have an odd product.No odd number is to the immediate left of another odd number.The 2 is immediately below the 5.***This week’s solution is courtesy of longtime cipher challenge competitor Kford-academy:**Full explanation:

(For clarity, let us label the statements as follows:

The 8 is between the 1 and the 5 on a straight line. (1)

There is a number in a corner that is the sum of the other two numbers in its row, column, and diagonal. (2)

The numbers in the left column have an odd product. (3)

No odd number is to the immediate left of another odd number. (4)

The 2 is immediately below the 5. (5)Let us also label the square as follows:

ABC

DEF

GHIHere is my method:

- By statement (3), A, D and G must all be odd, so the 2 cannot be in the left column.
- By statement (4), B, E and H must all be even, so the 5 cannot be in the middle column.
- By statement (5), the 2 cannot be in the middle column either, so the 2 and the 5 must both be in the right column.
- By statements (2) and (3), the number mentioned in statement (2) must be C or I, as otherwise it must be an odd number which is the sum of two odd numbers – which can never happen, of course.
- So the number mentioned in statement (2) must equal 7 (i.e. 2+5, see step 3).
- By statement (5), the 5 must be C or F (it must be in the right column – see step 3 – and if it was I, the 2 would not be in the square!).
- By statement (1) and what was implied in step 2, the 8 must be B or E (if it was H, the 5 must be I – which is impossible, see step 6).
- If the 8 was E, -1 must feature in the grid to satisfy statement (2) (see step 5 for clarification) – which is impossible, of course. So the 8 must be B.
- So the 5 must be C.
- So by statement (1), the 1 must be A.
- And by statement (5), the 2 must be F (and the 7 must be I from steps 4 and 5).
- By statement (2), the 6 must be E.
- Also by statement (2), G and H must equal 3 and 4 in some order (the only remaining numbers are 3, 4 and 9, and the only pair of numbers which add to 7 are 3 and 4).
- So D is 9.
- From what was implied in step 1, G cannot be 4 (i.e. 4 is even), so G is 3 and H is 4.

Solved!

- BOSS PUZZLE CHALLENGE 6 – open until Sunday 29th Nov 9am
OUR RESIDENT GUEST PUZZLEMASTER IS RODERICK KIMBALL, the fiend behind Enigami. Roderick was born in BC, making him either ridiculously old, or simply Canadian. In his youth, Roderick was sometimes spotted on the slow end of a soccer pitch but more often on the fast end of a chess board. (Surely you’ve heard of the notorious Kimball maneuver, in which one opens a chess match by flipping the king’s pawn into the air such that it lands, butter side up, on the king’s fourth rank.) Roderick has created puzzles for the National Museum of Mathematics, Games Magazine, Reader’s Digest Canada, NPR’s Ask Me Another and for his own amusement. In the other half of his life, Roderick has toured the world juggling with the Flying Karamazov Brothers. He also recently returned from Kenya, where he was sent by Engineers Without Borders to help folks with improving their water supply. He is proud to say that his ancestry includes two very great grandmothers who were executed as witches and he once made bottled water come out Rosie O’Donnell’s nose.

Arrange the numbers 1 through 9 in the grid so that all of the conditions in the puzzle are satisfied. Every number is used once. The rules are

*The 8 is between the 1 and the 5 on a straight line.There is a number in a corner that is the sum of the other two numbers in its row, column, and diagonal.The numbers in the left column have an odd product.No odd number is to the immediate left of another odd number.The 2 is immediately below the 5.* - BOSS PUZZLE Solution 5
Our fifth puzzle is one of Harry’s favourites, shamelessly stolen from Wikipedia

The King called the three wisest men in the country to his court to decide who would become his new advisor. He placed a hat on each of their heads, such that each wise man could see all of the other hats, but none of them could see their own. Each hat was either white or blue. The king gave his word to the wise men that at least one of them was wearing a blue hat; in other words, there could be one, two, or three blue hats, but not zero. The king also announced that the contest would be fair to all three men. The wise men were also forbidden to speak to each other. The king declared that whichever man stood up first and correctly announced the colour of his own hat would become his new advisor. The wise men sat for a very long time before one stood up and correctly announced the answer. What did he say, and how did he work it out?

SOLUTION – There is a great discussion about this over on the Forum, so I leave it to you to read it there!

- BOSS PUZZLE CHALLENGE 5 – open until Sunday 22nd Nov 9am
Our fifth puzzle is one of Harry’s favourites, shamelessly stolen from Wikipedia

The King called the three wisest men in the country to his court to decide who would become his new advisor. He placed a hat on each of their heads, such that each wise man could see all of the other hats, but none of them could see their own. Each hat was either white or blue. The king gave his word to the wise men that at least one of them was wearing a blue hat; in other words, there could be one, two, or three blue hats, but not zero. The king also announced that the contest would be fair to all three men. The wise men were also forbidden to speak to each other. The king declared that whichever man stood up first and correctly announced the colour of his own hat would become his new advisor. The wise men sat for a very long time before one stood up and correctly announced the answer. What did he say, and how did he work it out?

- BOSS PUZZLE Solution 4
Our fourth puzzle is from Mr. Enigma himself, Tom Briggs. It is rather different from the first three, in that we won’t be telling you what you need to do (at least at first). You will have to (try to) work it out for yourself. If you do manage it you should be able to find a hidden message so you will know. We will post a hint midweek if you are still stuck then.

Tom Briggs is a National Cipher Challenge veteran, having been introduced to it around a decade ago as a teacher when his Head of Department dropped a poster for it on his desk and said “you’re a nerd: do this.” He

*is*a nerd and he*did*do it, and never looked back: On a weekly basis he and his motley crew of codebreakers recruited on the sly from his maths classes got together to see what Harry and friends were up to. He learnt as much from his students as they did from him, and he eventually ended up at Bletchley Park itself, albeit a few decades too late to help out with the war effort. Now (with the help a shadowy figure known only as*Coronavirus Pandemic*) he has “gone rogue” and branched out on his own: he’s undercover as a maths teacher again, but working on some top secret projects that you can only find out about if you’re in-the-know (or just visit tkbriggs.co.uk )Did you figure out what to do? The numbers to the left and under the puzzle tell you to delete letters in blocks like a crossword, leaving a message that you could read, but backwards from the bottom right to make it tougher to see.

- BOSS PUZZLE CHALLENGE 4 – open until Sunday 15th Nov 9am
Our fourth puzzle is from Mr. Enigma himself, Tom Briggs. It is rather different from the first three, in that we won’t be telling you what you need to do (at least at first). You will have to (try to) work it out for yourself. If you do manage it you should be able to find a hidden message so you will know. We will post a hint midweek if you are still stuck then.

Tom Briggs is a National Cipher Challenge veteran, having been introduced to it around a decade ago as a teacher when his Head of Department dropped a poster for it on his desk and said “you’re a nerd: do this.” He

*is*a nerd and he*did*do it, and never looked back: On a weekly basis he and his motley crew of codebreakers recruited on the sly from his maths classes got together to see what Harry and friends were up to. He learnt as much from his students as they did from him, and he eventually ended up at Bletchley Park itself, albeit a few decades too late to help out with the war effort. Now (with the help a shadowy figure known only as*Coronavirus Pandemic*) he has “gone rogue” and branched out on his own: he’s undercover as a maths teacher again, but working on some top secret projects that you can only find out about if you’re in-the-know (or just visit tkbriggs.co.uk )You probably don’t know what to do! Good luck.

- BOSS PUZZLE Solution 3
Our third puzzle was from one of our forum regulars, Madness, and will be a familiar format, though Madness tells us it is the first Sudoku they have designed.

pronouns: mad, mad, mad’s

Very little is known about “madness”, but rumours abound.

Mad is thought to have worked in the cipher bureau of

the KGB until 1989, but lost everything in order to

escape the Soviet Union in a daring maneuver. A month later,

the wall fell. Quite disappointing, especially for mad’s

pocketbook. Now, we suspect, mad is hiding from FSB and

former Stasi agents in Scandinavia, Canada or the US. The

last person who claimed to have had direct contact with

madness disappeared in Oslo and has not been seen since.

We advise you not to try to find mad without state-level

support or some high-quality vegan cake.The solution comes from the-letter-wriggler:

Harry if you want to know, a follow up to my solution post.

Below is the order I solved it

USING FOLLOWING CELL REFERENCE NUMBERING

01 02

*_ || 04 05 _*|| 07 08 09

10*_ 12 || 13 _*15 ||*_ 17 18 19 20 21 || _*23 24 || 25*_ _*

——————————–

28*_ 30 || _*32 33 || 34 35 36

37 38*_ || _*41*_ || _*44*_ 46 _*48 || 49*_ 51 || 52 _**_ ——————————– _*56 57 || 58*_ 60 || 61 62 63 _*65 66 || 67 68 69 || 70 71 72

73*_ 75 || 76 77 78 || 79 _*81The __ is where the digit was given

there are 56 digits to be deduced.Step ==== [Cell] ======= Digit

01 Cell at [44] can only be 8

02 Cell at [35] can only be 6

03 Cell at [36] can only be 4

04 Cell at [18] can only be 1

05 Cell at [13] can only be 4

06 Cell at [34] can only be 9

07 Cell at [52] can only be 3

08 Cell at [15] can only be 3

09 Cell at [21] can only be 7

10 Cell at [33] can only be 7

11 Cell at [48] can only be 4

12 Cell at [68] can only be 4

13 Cell at [08] can only be 7

14 Cell at [05] can only be 9

15 Cell at [46] can only be 9

16 Cell at [09] can only be 8

17 Cell at [12] can only be 9

18 Cell at [78] can only be 9

19 Cell at [65] can only be 9

20 Cell at [23] can only be 6

21 Cell at [01] can only be 6

22 Cell at [24] can only be 8

23 Cell at [73] can only be 3

24 Cell at [72] can only be 3

25 Cell at [04] can only be 1

26 Cell at [51] can only be 6

27 Cell at [49] can only be 8

28 Cell at [81] can only be 7

29 Cell at [63] can only be 6

30 Cell at [76] can only be 2

31 Cell at [58] can only be 7

32 Cell at [67] can only be 6

33 Cell at [38] can only be 3

34 Cell at [28] can only be 8

35 Cell at [77] can only be 8

next no logic deduction so attempt…

36 Cell at [56] given value 1

37 Cell at [20] can only be 4

38 Cell at [02] can only be 5

39 Cell at [07] can only be 4

40 Cell at [10] can only be 2

41 Cell at [17] can only be 5

42 Cell at [19] can only be 1

43 Cell at [25] can only be 2

44 Cell at [37] can only be 5

45 Cell at [30] can only be 1

46 Cell at [32] can only be 5

47 Cell at [41] can only be 1

48 Cell at [60] can only be 5

49 Cell at [61] can only be 8

50 Cell at [57] can only be 2

51 Cell at [69] can only be 1

52 Cell at [70] can only be 5

53 Cell at [66] can only be 8

54 Cell at [71] can only be 2

55 Cell at [75] can only be 5

and finally

56 Cell at [79] can only be 1 - BOSS PUZZLE Solution 2
**BOSS agent F6exb used Excel as a tool to find the solution this week and was first to crack the puzzle. This is how they did it:**Hello Harry and Elves,

I apologize for my bad english but I think you can understand what I mean.

You asked me to write how I used Excel to solve puzzle #2.Excel only helped me to automate the calculations and do the job without

an eraser and pencil.

[Denis made an Excel(lent) spreadsheet with five rows and five columns. The top row computed the columns sums and the last row computed

the column products.

The first column computed the row sums and the last column computed the row products. Harry]And now, how I did it :

No even number is immediately to the left of another even number.

No odd number is immediately below another odd number.

===> odd and even number alternate.From 1 to 9 there are 5 odd numbers and 4 even numbers.

So the square begins with an odd number, and every corner plus center

is odd.In the lower left corner, I wrote the formula to add the 3 other

corners, but I know that it is 9, and 7 can’t be in a corner. So 7 is in

the center square.There is a column with a sum of 10.

It is not the first column because of the 9, nor the second because of

the 7. So it is the last column.One row has a product of 30.

30 = 2 * 3 * 5 or 30 = 1 * 5 * 6. It is the first row.There is a row with a sum of 21.

It is the second or last one.

With a 9 in the lower left corner, we need 9 + 7 +5 or 9 + 6 + 6, it is

impossible.

7 is already in the center square so it is the second row. We need 14

more so we have 8 and 6 in this row.To have 10 in the last column we must have the 6 on the right of the 7.

One row has a product of 30. (Again)

30 = 2 * 3 * 5 or 30 = 1 * 5 * 6. It is the first row. But with the 6 in

the second row, the first row is 2 * 3 * 5.Now it is quite finished. 4 is in the middle of the last row and with a

little cut and try with Excel, it is done.

F6EXBArrange the numbers 1 through 9 in the grid so that all of the conditions in the puzzle are satisfied. Every number is used once. The rules are

*The number in the lower left corner is 4 times the number in the upper right corner.**The 9 is between the 5 and the 8. (on a straight line)**There is a column in which the sum is equal to the product.**The 4 is between the 9 and the 3. (on a straight line)**No prime number is immediately to the left of a prime number.*

- BOSS PUZZLE CHALLENGE 3 – open until Sunday 8th Nov 9am
Our third puzzle is from one of our forum regulars, Madness, and will be a familiar format, though Madness tells us it is the first Sudoku they have designed.

pronouns: mad, mad, mad’s

Very little is known about “madness”, but rumours abound.

Mad is thought to have worked in the cipher bureau of

the KGB until 1989, but lost everything in order to

escape the Soviet Union in a daring maneuver. A month later,

the wall fell. Quite disappointing, especially for mad’s

pocketbook. Now, we suspect, mad is hiding from FSB and

former Stasi agents in Scandinavia, Canada or the US. The

last person who claimed to have had direct contact with

madness disappeared in Oslo and has not been seen since.

We advise you not to try to find mad without state-level

support or some high-quality vegan cake.You know what to do!

- BOSS PUZZLE CHALLENGE 2 – open until Sunday 8th Nov 9am
Our second puzzle is another from Roderick Kimball’s Enigami stable IS RODERICK KIMBALL, the fiend behind Enigami. Roderick was born in BC, making him either ridiculously old, or simply Canadian. In his youth, Roderick was sometimes spotted on the slow end of a soccer pitch but more often on the fast end of a chess board. (Surely you’ve heard of the notorious Kimball maneuver, in which one opens a chess match by flipping the king’s pawn into the air such that it lands, butter side up, on the king’s fourth rank.) Roderick has created puzzles for the National Museum of Mathematics, Games Magazine, Reader’s Digest Canada, NPR’s Ask Me Another and for his own amusement. In the other half of his life, Roderick has toured the world juggling with the Flying Karamazov Brothers. He also recently returned from Kenya, where he was sent by Engineers Without Borders to help folks with improving their water supply. He is proud to say that his ancestry includes two very great grandmothers who were executed as witches and he once made bottled water come out Rosie O’Donnell’s nose.

- The number in the lower left corner is the sum of the numbers in all the other corners.
- There is a column with a sum of 10.
- No even number is immediately to the left of another even number.
- One row has a product of 30.
- There is a row with a sum of 21.
- No odd number is immediately below another odd number.

- BOSS PUZZLE Solution 1
**Here is the letter wriggler’s solution:**

1] can only be 4 & 1 or 8 & 2 must be 8-2 because b] 4 is between, not at edge.

2] the 9 must be above the 8 (not the centre – the 2 blocks it) making Top Left 5

3] out of the 9 digits only 2, 3 and 1<see d] satisfies this, 2 is already placed

4] 9 is placed so 9, 4 and 3

5] check for no double primes – ok*The number in the lower left corner is 4 times the number in the upper right corner.**The 9 is between the 5 and the 8. (on a straight line)**There is a column in which the sum is equal to the product.**The 4 is between the 9 and the 3. (on a straight line)**No prime number is immediately to the left of a prime number.*

- BOSS PUZZLE CHALLENGE 1 – open until Sunday 25th Oct 9am
OUR FIRST GUEST PUZZLEMASTER IS RODERICK KIMBALL, the fiend behind Enigami. Roderick was born in BC, making him either ridiculously old, or simply Canadian. In his youth, Roderick was sometimes spotted on the slow end of a soccer pitch but more often on the fast end of a chess board. (Surely you’ve heard of the notorious Kimball maneuver, in which one opens a chess match by flipping the king’s pawn into the air such that it lands, butter side up, on the king’s fourth rank.) Roderick has created puzzles for the National Museum of Mathematics, Games Magazine, Reader’s Digest Canada, NPR’s Ask Me Another and for his own amusement. In the other half of his life, Roderick has toured the world juggling with the Flying Karamazov Brothers. He also recently returned from Kenya, where he was sent by Engineers Without Borders to help folks with improving their water supply. He is proud to say that his ancestry includes two very great grandmothers who were executed as witches and he once made bottled water come out Rosie O’Donnell’s nose.

*The number in the lower left corner is 4 times the number in the upper right corner.**The 9 is between the 5 and the 8. (on a straight line)**There is a column in which the sum is equal to the product.**The 4 is between the 9 and the 3. (on a straight line)**No prime number is immediately to the left of a prime number.*