A Sudoku With Only 4 Given 'Digits'?!

Today is Aad van de Wetering's 77th birthday and he's created this puzzle to celebrate. Aad's puzzle which featured in our video called "A Sudoku With Only 4 Given Digits" has now been viewed over 7 million times and this puzzle also only has 4 givens - if you count those large 7s as digits!! This is another brilliant creation from the great man and you can play it at the following link:

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Rules:
Normal sudoku rules apply. Digits in green cells sum to 77. Adjacent digits on a grey line must differ by at least 4.

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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.

Thank you for watching!
Simon and Mark

[danielputnam]

Let's all whisper together now. Gefeliciteerd Aad.

[pelahnar]

I enthusiastically raised my hand when Simon missed the fact that the given 5 didn't change the parity. Unfortunately, I was alone in my room, watching a prerecorded video of someone else solving this puzzle, so no one called on me for the answer

[CroixMedia]

Filling in the green squares all at once felt like blowing out the candles on a cake. Wonderful!

[RoderickEtheria]

22:53. Simon is absolutely right that he can't change the parity twice, but a 151 doesn't change the parity at all.

[TheSonicPerson]

I loved the part where the green cells could only be 8s and 9s because they Aad to 77 and therefore force what goes on the two large 7s.

[Wildhorn]

This puzzle showed us that Simon has a very hard time to do both sudoku and puzzle rules at the same time. It is either one or the other and he has to "switch" between them.

[th.nd.r]

Great setting and solving once again. Happy birthday Aad! The fact that Aad was able to create a sudoku that was (1) doubly, even triply thematic, (2) aesthetically pleasing, (3) well-set, (4) uniquely his, and (5) seemingly unsolvable at first glance is just so cool. And who else to figure it out and explain everything so well than Simon. Hats off to both of you.

[inspiringsand]

Rules: 04:23
Let's Get Cracking: 05:09
Puzzle Solved: 35:14
Simon's time: 30m05s

What about this video's Top Tier Simarkisms?!
Bobbins: 1x (11:16)
Three In the Corner: 1x (32:14)

And how about this video's Simarkisms?!
Clever: 9x (02:27, 02:35, 02:39, 02:42, 16:42, 16:42, 23:55, 23:57, 35:47)
By Sudoku: 7x (13:20, 20:51, 21:16, 25:37, 27:18, 28:36, 33:36)
Sorry: 5x (14:18, 20:56, 23:17, 23:39, 26:39)
In Fact: 5x (00:23, 00:48, 11:36, 19:33, 24:59)
Beautiful: 4x (20:04, 21:03, 25:05, 25:22)
Naked Single: 3x (32:01, 32:32, 33:10)
Good Grief: 2x (15:44, 34:53)
Goodness: 2x (16:47, 21:08)
Take a Bow: 2x (16:47, 16:50)
Hang On: 2x (05:19, 28:19)
Magnificent: 2x (35:19, 36:34)
Obviously: 2x (13:54, 31:19)
Progress: 2x (01:52, 21:52)
What on Earth: 1x (05:21)
The Answer is: 1x (30:18)
Nonsense: 1x (28:36)
In the Spotlight: 1x (32:16)
Brilliant: 1x (01:10)
Ridiculous: 1x (20:02)
Oh It Can!: 1x (31:01)
My Phone is Buzzing: 1x (30:32)
Famous Last Words: 1x (32:56)
Bizarre: 1x (06:28)
Surely: 1x (30:18)
Corollary: 1x (19:41)
Phone is Buzzing: 1x (30:32)

Most popular number, colour and box this video:
Five (72 mentions)
Green (13 mentions)
Box 8 (2 mentions)

Antithesis Battles:
Low (37) - High (16)
Odd (5) - Even (1)
Higher (2) - Lower (0)

FAQ:
Q1: What is a Simarkism?
A1: A Simarkism is something that Simon and Mark typically or frequently say.
Q2: How do you do this so fast?
A2: I'm not made of flesh and blood, but of sand ...
Q3: Why don't you include 'XX' and 'YY'?
A3: Probably it's already on the list ('Scooby-Doo' for example), but not mentioned in this video. But if you think it's not, tell me what you'd like me to include and there's a good chance I'll add it!
Q4: You missed 'XX' at 'YY:ZZ'!
A4: That could very well be the case! Human speech is hard to understand for computers like me, especially British sometimes! Point out the ones that I missed and maybe I'll learn!
Q5: Could you turn these statistics into videos?
A5: I've been playing around with the idea and I'm open to input as to what people would like to see. Let me know if you are interested in this and/or have suggestions.

[TheSonicPerson]

25:31 The parity needed to change an Aad number of times

[rossylittle]

Happy birthday Aad! Amazing puzzle as always. Hope we see new puzzles for years to come

[orogenesis]

13:27 for me. Happy birthday Aad! How fitting to solve an elegant puzzle with a throwback title in your honor. It was your 4-digit sudoku that introduced me to Cracking the Cryptic, and for that I will be forever grateful.

[RichSmith]

At 11:50, Simon marked r6c2 as red because it couldn't be "a parity changing 5". He didn't rule out the possibility of it being a 5 surrounded by two 1s (even though this was trivial because of the given 1 in r7).

Every other cell marked red was explicitly ruled out from being a 5, full stop.

So when he marked high and low digits as either 6789 or 1234, at 19:50, he should have included 5 as still an option for the "high" digits in r6c2. Fortunately, this doesn't alter the rest of the solve though. When he later gets around to removing 6 as an option, around 21:50, he could also have trivially removed 5 as an option, had it been present.

[RedPandaLesbian]

It always tickles me when Simon staunchly refuses to do sudoku in sudoku puzzles :P wonderful setting and very happy birthday Aad!

[jkid]

19:19 I hate to say this, but 5 still counts as both a high and a low digit here and moving forward, even if it doesn't change parity. You have to rule out 5s by saying things like "if this was a 5 it would have a 1 or a 9 on either side of it, and they're in the same row, so it can't be"
Happy birthday Aad! Lovely, personal puzzle.

[longwaytotipperary]

Happy birthday, Aad!! 🎈🎈🎈🎈🎈🎈🎈 x 11!!

[ICHMUSSMALPIPI]

Sudoku setters never cease to amaze me, amazing puzzle and great solve. Happy birthday Aad

[bertbergers]

Van harte gefeliciteerd met je verjaardag meneer van de Wetering !

Bedankt voor al veel prachtige content verfilmd door Simon en Mark.

[Raven-Creations]

Very nice, and happy birthday to the Dutch Master.
I had a similar approach to the break-in, although I was looking for where a 159 sequence was possible.

[davidhughes]

Happy birthday Aad, thank you for the beautiful puzzle. Another lovely solve thank you Simon.

[Zardox]

Happy Birthday, Aad!
And thanx for the lovely puzzle!
It's like you gave all of US a gift for your birthday!
🎂🎉🍾🍻