No Swearing Allowed,Despite the Puzzle ...

Normal sudoku rules apply.
Adjacent digits on green lines must have a difference at least 5, unless one of them is 5.
Digits in cells joined by a black dot have ratio 1:2, unless one of them is 5.
Digits in cells joined by V sum to 5, unless one of them is 5.
Digits in cells joined by X sum to 10, unless one of them is 5.

▶ SUDOKU PAD - Our New App ◀ NOW AVAILABLE - You can now input your own classic sudoku puzzles into our software using our new App! The app also comes with 12 handmade puzzles from us and it is NOW AVAILABLE at these links:
On Amazon: Search for “SudokuPad”

▶ OUR PATREON PAGE – JOIN THE COMMUNITY, SUPPORT US AND TRY OUR PUZZLE HUNTS◀

▶Our merchandise is all here: ◀

▶ CTC FAN DISCORD SERVER◀

▶ OUR BACK CATALOGUE – ALL CATEGORISED WITH LINKS!◀

▶ WHY NOT TRY OUR CLASSIC SUDOKU APP? ◀

▶ OUR KILLER SUDOKU IS ALSO AVAILABLE◀

▶ YOU CAN ALSO TRY OUR SANDWICH SUDOKU APP ◀

▶ TRY OUR CHESS SUDOKU APP◀

▶ HERE’S WHERE YOU CAN TRY OUR MIRACLE SUDOKU APP◀

▶ THERMO SUDOKU is available too!◀

▶ YOU CAN ALSO TRY OUR ARROW SUDOKU APP ◀ Here are the links:

▶SEND US PUZZLES TO SOLVE/CONTACT US◀
Snailmail: Mark Goodliffe, Box 102, 56 Gloucester Road, London SW7 4UB

▶FOLLOW US◀
Twitter: #crypticcracking
@crypticcracking

▶Music◀
Tim McCaskey (Guitar) or Lucy Audrin (Piano) or Riffclown plays Mozart's Sonata no 16 ("Sonata Facile")
▶SOFTWARE◀
Play the puzzle in the video by clicking the link under the video (above). Thanks to Sam Cappleman-Lynes and Sven Neumann for their work.
▶Logo Design◀
Melvyn Mainini

▶Opening Credits Design◀
Joel Blundell

▶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

[dusanpokorny]

Hi Mark, filuta here, thanks a lot for featuring my puzzle, ir was a pleasure to see you fight it!

[bluji]

Before Mark even finished the rules, I'll make a prediction: this is a f**e out of f**e sudoku.

[mallomon]

All but one of the 5's is next to a 4, which I found interesting, since the letters left out of f**e are iv, the Roman numeral for 4.

[inspiringsand]

Rules: 02:01
Let's Get Cracking: 03:55
Mark's time: 1h8m31s
Puzzle Solved: 1:12:26

What about this video's Top Tier Simarkisms?!
Three In the Corner: 1x (1:08:16)

And how about this video's Simarkisms?!
Ah: 11x (06:31, 32:38, 37:33, 39:51, 46:43, 57:15, 1:02:19, 1:04:43, 1:05:09, 1:06:49, 1:12:13)
Sorry: 9x (10:26, 16:19, 20:44, 22:07, 32:57, 34:04, 41:04, 42:08, 1:09:35)
Brilliant: 6x (00:27, 14:45, 14:45, 39:51, 1:12:53, 1:12:53)
In Fact: 6x (14:14, 22:47, 37:07, 44:57, 1:09:00, 1:11:11)
Useless: 5x (04:46, 05:30, 38:37, 41:59, 42:05)
Hang On: 5x (11:17, 44:47, 59:19, 1:00:28, 1:12:04)
Obviously: 5x (05:40, 32:24, 53:42, 1:00:14, 1:08:09)
Good Grief: 4x (23:26, 35:46, 53:14, 58:55)
Fascinating: 4x (02:01, 03:36, 41:13, 59:31)
Goodness: 3x (07:00, 45:13, 59:50)
Irritating: 2x (40:13, 1:06:37)
Intriguing: 2x (01:37, 01:37)
Wow: 2x (16:42, 27:26)
Pencil Mark/mark: 2x (05:33, 1:10:54)
What on Earth: 1x (04:18)
Bother: 1x (15:49)
The Answer is: 1x (1:01:58)
Clever: 1x (37:47)
Ridiculous: 1x (14:55)
Deadly Pattern: 1x (1:12:20)
By Sudoku: 1x (36:44)
Surely: 1x (53:21)
Progress: 1x (41:10)
What Does This Mean?: 1x (09:47)

Most popular digit and colour this video:
Five (250 mentions)
Black (23 mentions)

Antithesis Battles:
High (33) - Low (31)
Even (10) - Odd (7)
Black (23) - White (0)
Column (17) - Row (6)

FAQ:
Q1: You missed something!
A1: That could very well be the case! Human speech can be hard to understand for computers like me! Point out the ones that I missed and maybe I'll learn!
Q2: Can you do this for another channel?
A2: I've been thinking about that and wrote some code to make that possible. Let me know which channel you think would be a good fit!

[puritan]

This is surely one of the most fiendish puzzles I have seen, what kind of mind can set this!! I have watched the whole video and I am certain I still could not solve this, half the time I couldn't even follow how mark came to his conclusions!

[emilywilliams]

This was quite amazing. A kind of liar puzzle, I would say, but the lies are very clearly telegraphed if only one could find that elusive five! I confess, I could not have solved this puzzle in a week if my very life depended on it - well done, Mark. Toward the end, after your interruption, you wondered if it had been flowing along before you were gone or you finally had seen things that you should have seen - I think you were beginning to hit the flowing part, and would indeed have finished the puzzle in just a few minutes had the phone not rung and you not had to go to pick up your son. You only just had filled in most of box 3, and from that is where the other quick digits cascaded after your return. So no worries there. Tonight's lovely vocabulary included "recondite" and "mendacity." I love telling people that I have to consult my dictionary during a sudoku video! And I laughed out loud at the telling pause in, "If that's a deduction I could have made ages ago ... the swear words aren't enough." If it is any consolation, I don't think it would have been ages ago at that point; an age is a very, very long time, after all. Amazing puzzle, amazing solve, amazing video. Thank you so much, Mark.

[KyleZelenak]

59:50 If you hypothesize the (14) cell in box 8 to be a 1, it eliminates the 1 from the (15) cell in box 9 making it 5, thus eliminating the 5 from the (56) cell back in box 8, making that a 6. If it's a 6 at that point, its neighbors on the whisper line need to be 1 and 5. This wouldn't be possible however, because you would have used the 1 for box 8 in the beginning of the hypothesis.

Bottom line, the (14) cell in box 8 could be found to be a 4 in a possibly simpler way, as Mark asked.

[josephrion]

22:50 the other side of 8 is 3. In column four, and you can't have a 36 pair in t the column if you let it in so the center is 2 with 8 and 7 flanking it. Therefore you should be able to determine where the five goes considering you can now anchor two to the middle.

[darleneofthetallpines]

I am amazed that this puzzle has a unique solution. WOW!

[dariusm]

It is possible to make deduction, at 1:02:30, much earlier in the puzzle by considering where 4 can go on the whisper line and where it is possible to place the 9/5 pair needed to surround it. This narrows 5 to the 2 spaces in top left of whisper line and sets the high low order for the other squares in Box 7.

[thomasbui]

Woah over an hour from MARK?! That's new

[BigAsciiHappyStar]

Hopefully this should make up for all the times 5 has been unfairly maligned as the most useless digit in a XV Sudoku #istandwithfive

Haven't tried this one yet - something to look forward to after work :)

[quack]

that was a satisfying solve... tricky throughout. thanks for sharing!

[deathrow]

at 19:00 Mark deduces that the black dots on c4 must be 36 and 5 something, then at 22:00 looks into the possibility of 56 on the x and only pencil marks up to the 97. If he had taken it one step further he would have seen that that is impossible, as that puts a 3 on c4, making his EARLIER deduction of the black dots on c4 impossible.

[joelstevens]

I know this is late (I’ve had trouble keeping up with the sudoku videos more recently) but I believe this is a ‘simple’ break in (though along similar lines). First of all, 4 and 6 must both be next to the 5 in box 5, since we cannot repeat the digit 1 or 9. This creates a sequence (using the rules of German whispers lines) where each pair of digits (one for each direction) except 5 adds to 10. Only the 2, 8 pairs are next to each other in this sequence so the 10 (X) domino in box 5 is therefore either 2, 8 or it doesn’t add to 10 and has a 5 on it (note that any domino which is incorrect must include a 5 by the rules). Placing 2 and 8 on this 10 domino puts a 19 pair on the 10 domino and black kropki (dot) in column 5, making that 10 domino incorrect and the black kropki correct (or else both would contain a 5 which would repeat in the column). However, the only option for the black kropki is then 1 and 2 which will break the German whispers line. Thus, the 10 domino in box 5 contains a 5 and one of 4 or 6. By following the whispers line, 2 and 8 must now appear in column 4 in box 5 and since one of the black kropki in column 4 has to be correct (or else 5 would repeat again), one of those kropki is a 3, 6 pair (the other 3 options are all ruled out by the 2 and 8). This rules 8 out as the digit in row 5 column 4, so it must be a 2 (2 and 8 are next to each other) which makes the 10 domino in the box a 4, 5 pair. If 5 was in row 5 column 5, the dominoes in column 5 could not contain 5 so would be 12 and 37 but neither 2 nor 7 could be next to a 3, 6 on a whispers line, which would break the black kropki in column 4 (neither could be 3, 6), so the digit in row 5 column 5 is a 4.

Incredible puzzle (both the idea and its execution), thanks to Filuta and well done Mark for getting through it! As hard a sudoku as it was, I really enjoyed it. :)

[Piatato]

I struggled mightily with this one myself! 😅 It's an awesome puzzle, and I'm looking forward to see how Mark handles it!

This was a great video! My favourite CTC video in quite a while.

[Freelancer_]

The key is that the 3 in Col4 must either be in Box2 or Box8, and cannot be in Box5. So the possible sequences put a 54 pair in Row5. Then the other cells in Box5 (by Column), are 69 in Col6, 13 in Col5, 78 in Col4 with 2 in R5C4 no matter which way around they go. That forces 19 in the X domino of Row5, and 36 in the black dot domino of Row5, with 78 in R5C3/R5C7. Now, the Whisper loop in Box5 has to have 15 opposite the 6 and 7 or 8. That's the break-in.

[GrahamRSteele]

That one just did not give up. Wow. Exhausting but I'm strangely satisfied.

[AndrewYakovenko]

That was a crazy one. It took me almost 3 hours, but felt so good when I cracked it!