Practise Your Skills with this Sudoku

Normal sudoku rules apply. Adjacent digits along a green line must have a difference of at least 5. Cells joined by a black dot have a ratio of 2:1. A cell with a filled circle must be odd. A cell with a filled square must be even.

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1 August saw the release of our monthly Patreon Reward, “Tennis Anyone?” in which six clever sudoku puzzles themed around tennis are served up by Glum Hippo and us. Solve the puzzles and determine the final answer to the hunt by August 20 to be in with a chance at the prize. Join us at the $2/month level or higher for the monthly reward, $3/month or higher to have access to solution videos. (Any member has access to a Patreon-only discord channel to discuss the puzzles and get help!)

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▶Credits◀
Music: Tim McCaskey (Guitar) or Lucy Audrin (Piano): Mozart's Sonata no 16; and Mark’s outro music by Riffclown.
SOFTWARE: Thanks to Sam Cappleman-Lynes and Sven Neumann
Logo: Melvyn Mainini
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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
▶ Contents ◀
0:00 Theme Music & Rules of today’s puzzle
2:08 News around the channel
2:41 Start Of Solve - Let's Get Cracking!

[brendonmurley]

22:06 - I’m sure that’s much slower than most other folk, but I’m absolutely delighted - it’s the first one from the channel I’ve ever solved without watching any of the video first! Huzzah!

[oxjphs]

It's an honor to have a puzzle featured on the channel! I came across CTC a couple years ago and have been solving along ever since. I have often been baffled by the immense creativity of the setters featured on the channel, and I was finally inspired to give setting a try myself (turns out it's harder than I thought!). Thanks for all the work you guys have done to highlight the wonderful creations of setters around the globe. Hopefully, this puzzle is the first of many as I continue improvising my puzzle making skills!

[roielia]

Using the Phistomefel ring, after finding the polarity of the ring you can discover that 4s and 5s can't live on the ring, and therefore can't live in the corners. It helped me deduce the dots in the corner in no time, and made the puzzle relatively easy.

[emilywilliams]

That is a nice puzzle, I agree, Mark, is has a nice flow to it. I am glad to know why the 1248s and the 36s are unable to peacefully coexist around the black dot picnic; American musical comedy would make it out to be the dispute between the Sharks and the Jets, of course (but so derivative...) Thanks for the video.

[SudokuConCarabet]

I’m so proud of myself. I actually used the phistomophel theorem to determine there were no 4’s in the corner 4-squares.

[TravisCrump-hyke]

This makes me feel better for just pencilmarking the odds and evens first thing so I don't forget.

[globglogabgalabyeast]

Lol, I missed the simple break-in of 13 pair on the line not working in r5 or c5, but found a cool break-in that could be used for a puzzle with a similar setup

Looking at only the ring and the central box, note that the corners of the ring will either be 2 6s and 2 8s or 2 2s and 2 4s. In the latter, two opposite corners must be 4s, giving 9s on both sides of each 4 by the whisper line. This then forces a 9 into r5c5, which breaks because of the black dot. Note that this immediately gives the polarity of the line and a 1 in r5c5!

[steve]

8:45 for me. Fun puzzle - just barely harder than GAS level (assuming you remember that the squares are even😛).

[KevinAnnLowery]

If you pencilmark the even/odd squares, you'll notice that either 2 corners have to be 6s or 4s (surrounded by 1s or 9s) and that forces the corners to be high, because if they were 4s you would rule out 9 from the center box due to the black dot touching the central cell. (I forgot the whole point of starting this comment.) 1 is therefore placed in the center cell and you can start the puzzle with a placed 1+2 kropki dot in box 5. Along with some instantly placed 5s as well.

[Trizzak]

Even-Squares to the OG Goodliffer: "Am I a joke to you?"

[etienneschramm]

I managed it in just over 15 minutes. Really nice puzzle, great job oxjphs!

[psymar]

oh my god I have never screamed at one of your videos more. as soon as you get the circles on the line being 79, you can get the corners being 68, and this makes the puzzle fall apart very quickly, particularly since it locks a 1 on each side of the square. Definitely GAS-level if you pencilmark the odd/even digits before doing anything else.

[gavindeane]

Thanks for highlighting the idea of being misled by the black dot sequence in rows 3/4 columns 1/2 at the end of the vide Mark. I did indeed make exactly that mistake. Three times! Each time, I got a good way through the puzzle before it broke - in a different way each time. Could not figure out what I was doing wrong until I watched the video.

[stevesebzda]

That did it (not breaking the"1, 3s" ) which gave ya the high/lows.

Nice, at 5:32.
That did it.
Thanks, Mark.

[Coyotek]

8:27 ... short and sweet; happy to have an easier one in my vacation backlog to solve

Nice puzzle!

[barrydavies]

I like the idea that 7 & 9 have joined 6&8 as high even digits. Great fun solve. Thanks Mark.

[deangaudet]

12:01 for me... i'm surprised mark didn't pencil mark in the evens/odds to start, i usually just get that out of the way early so i don't have to remember which is square/circle.

[markp]

9:15 finish. A nice easy logic path to the finish, not too difficult to see. Fun!

[jmleewong]

"That's Mark solving Sudoku." Needs a Tee-Shirt!

[neokart]

At minute 17:00 it seems that Kropki Dot in C2 is unnecessary. 2 can only be in r5c1 in box 2, then: r3c1=4, then: r3c2=2. The 4 on r3c1 interacts with the 4 on r6c9 and only leaves a spot for the 4 on box4. I have no right or desire to judge any creation, it just seemed strange to me because said Kropki Dot doesn't seem to make the puzzle much easier (or difficult) either.
PS: It's also possible that the dot adds a factor of confusion with the issue of sequence 124 or 248 that Mark mentions.