No digits in this sudoku? AGAIN!

Normal sudoku rules apply, and blue cells contain the sum of their (orthogonally) neighbouring cells.

Miracle Sudoku is out on Android, Steam and App Store.

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Play the puzzle in the video by clicking the link under the video (above). We are building a website which will allow you to enter your own sudoku puzzles into the software and this is coming soon!

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▶ABOUT US◀
Hi! We're Simon Anthony and Mark Goodliffe, two of the UK's most enthusiastic puzzle solvers. We have both represented the UK at the World Sudoku Championships and the World Puzzle Championships. We're also "cryptic crossword" aficionados. Mark is the twelve-time winner of The Times championship and Simon is the former record holder for most consecutive correct solutions to The Listener crossword. We hope we can help your puzzle solving while also introducing you to some of the world's best puzzles.

Thank you for watching!
Simon and Mark

[dolevsacher]

There actually is a faster way start:
Cells 2, 3, 4, 6, 8 in box 1 sum to at least 15;
cells 2, 4, 6, 7, 8 in box 2 sum to at least 15;
cells 3, 6 in row 4 sum to at least 3;
and finally, r3c7 it least 1.
In total, they sum to at least 34.
However, their sum is also the sum of the blue cells in boxes 1 and 2, which are at most two 8, 9-pairs.
Therefore that sum is indeed 34, and we can put it quite a lot, including a digit!

[bluji]

I'm just waiting for the day when we have a title "Digits at the Start? Unbelievable!"

[DyingFlutchman]

And that is the 600th video by Mark!
Congrats with this milestone!

It's incredibly fascinating to see you race through difficult puzzles. Perhaps even a bit insulting to setters :)

Huge thanks from me and all puzzle lovers!

[MrBenztwn]

My (easier) break in was: The sum of the cells neighbouring the 4 blue cells in boxes 1 and 2 combined is at least 30 because there are 5 neighbouring cells in each box ((1+2+3+4+5)x2). Then there are still 3 remaining neighbouring cells to the blue cells with a minimum sum of 4 (1+2+1). That equals 34 which means that the 4 blue cells must be 2 8's and 2 9's. The neighbouring cell next to the right blue cell in box 2 must be a 1 and the neighbouring cells under the boxes 1 and 2 must be 1 and 2 to get to that minimum.

[paulcook]

I really loved this puzzle. Of all the puzzles published on this channel APART from classic sudoku, it has the most minimal combination of rules plus information in the grid (i.e. cages, lines, arrows, thermos, etc) yes still is challenging and has a beautiful solution.

I started in roughly the same way as Mark, looking at row 3 but didn't persist with it as long as he did. In the end (after a few other failed starts e.g. focussing at column 9 and row 9 and box 7 etc. which led nowhere) I eventually found looking at box1&2 together worked (as other commenters have noted). I found it really helped to shade all the blue's neighbours yellow. Then the yellow cells in boxes 1&2 add to minimum 30 and the ones "sticking out" add to minimum 4. Bingo! The blues must be 8989 and the yellows are all minimum. So I was perhaps slightly ahead of Mark time-wise at this point. But all the routine stuff thereafter he is super quick at. So I finished in about the same time. But allowing time for explaining and talking, he's still faster.

[seanmcdonough]

I'd like to join in on the side of saying it's ok to write in and "bifurcate" to rule something out. If nothing else, it would be easier to follow some of the times and especially when you already know it is quickly not going to work and are just trying to explain so we can see the contradiction easier.

[PriusMike]

Cracking the Cryptic is the best thing to come to America since America

[papalyosha]

At the beginning you can look at the neighbors of four blue squares in boxes 1 and 2. There are total of 13 neighbors: 5 in box 1 (with sum of at least 15), 5 in box 2 (again with sum of at least 15), 2 in row 4 (with sum of at least 3) and 1 more cell. So the total sum is at least 34. But it is a sum of four blue cells which are at most 2*(8+9)=34. So there is no freedom.

[chiarabookworm]

I wish in that beginning set of logic he would have just put the numbers in. It’s easier for us to follow his logic and for him to keep track of where he is in his own logic.

[Tehom]

"You're not Simon, I'm not lying to you". Heh. Or sad face, if you two are feuding for real, but I think you are not.

[RichSmith]

This just repeats what other comments have pointed out, but since I was quite pleased to spot this for myself, I'm going to explain it anyway...

Consider the four blue cells in boxes 1 and 2. They have 13 non-overlapping orthogonal neighbours. Five are in box 1, all have to be different digits, minimum they can be is 1+2+3+4+5 = 15. Also five in box 2, minimum 15. Two are in row 4, minimum 1+2 = 3. One additional in box 3. Combined they have a minimum of 15+15+3+1 = 34.

The four blue cells can have a maximum of 8+9+8+9 = 34.

Since these are the same, there are no degrees of freedom. The blue boxes have to be 8, 9 pairs. The one neighbouring cell in box 3 has to be a 1. The two cells in row 4 have to be a 1, 2 pair.

This break-in makes reaching the point Mark reached at 33:10 a lot easier. Probably took me a little over 5 minutes to reach here. (Then Mark solved the rest of the puzzle in 6 minutes, whereas as it took me 20 to finish. 😂)

It was impressive that Mark was able to finish at all, without seeing the "easy" break-in. Definitely turned a medium difficulty puzzle into a monstrously difficult puzzle.

I'll also repeat other's pleas for Mark to show us his thought processes by entering digits into the grid, when examining possible paths. Yes, it's an impressive feat that your can do it in your head, Mark. But it doesn't make for an enjoyable video to watch. You could at least put the digits in the grid, for the benefit of the viewer, after you have reached your conclusion. "This cannot be a 3 and this is why..." approach.

[Paolo_De_Leva]

Phenomenal construction. It fully deserved to be included in volume 2 of *CTC Greatest Hits.*
👏👏👏👏👏👏👏👏👏👏

[esragunac]

I really love their Turkish pronounciations, very funny with the Ğ sound which is not actually a sound, just a way to prolong the previous letter. Great video, by the way!

[DanielAydarArantes]

I'm astonished by the solution and the spacial visualization Mark have. Kudos!

[Coyotek]

33:33 ... which is ironic, as I spent the beginning of my solve proving where 3s *couldn't* go (very much 'brute force', though with reasoning behind where to start with that). Once I ruled out 3s from four different cells, I was able to find a more logical path and eventually finish the solve.

Nice puzzle!

[simpledude]

After about six minutes of logic I never would’ve thought of:
“I’ll see myself out” :)

[MattYDdraig]

19:43
Brilliant concept and cunningly tricksy.

[jeffreytennant]

This has to be one of the most amazing constructions (and pretty much one of the most amazing solves) I have ever seen.

[terracottapie]

28:17 "Ah, the relief of getting something in!!" -- Cracking the Cryptic, AFTER DARK

[thorns]

The start was a bit painful. Teh 5 cant be next to the 8 becaus 5+2+1+1=9. You can't have three ones orthogonally adjacent to the same square. This makes it extraordinarily hard tofollow the reasoning.