A Sudoku With Only 4 Given Digits?!

You can try this quite remarkable construction by Aad van de Wetering here:
Normal sudoku rules apply. In addition, both marked diagonals must also contain the digits 1 to 9. Cells that are a knight's move apart (in chess) cannot contain the same digit. The central 3x3 box must form a magic square.

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▶SOFTWARE◀
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!

▶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

[jonandmoni]

Wife: what are you doing still looking at your phone at 2 AM?
Me: looking for naked singles in this area.

[bluexix]

'Puts down a 5 in the middle'
Oh yeah, it's all coming together

[slowdtunez]

That must be a 5 there
Me: couldn't agree more

[sameepsapkota]

Never in my 19 yrs of existence would I have ever agreed with anyone that one day at 2 in the morning I would be watching a guy playing sudoku

[Kordellcabe]

I was lost almost the entire time but I figured out the final nine before he did and frankly that’s win in my book.

[brianbernstein]

I yelled "7" at this guy and he figured out my credit card number minutes later

[Afriendd]

"We're actually able to finish the magic square, I don't know why I'm surprised by that but I just am." Yeah cant believe we solved it, we're a great team.

[QuilloManar]

Did I just watch a man solve a sudoku puzzle for 25 minutes with no background music or personal interest in sudoku? Yes, yes I did.
Was I thoroughly engrossed the entire time? Yes, yes I was.

[seth]

It's quite interesting how these knights move puzzles tend to end up rotationally symmetric. If you rotate the puzzle 180 deg and overlay it with itself, all cells sum to 10 (in other words, when reflected through the center point, all 1s land on 9s, 2s on 8s, 3s on 7s, 4s on 6s, and 5s land on themselves).

[droe]

This is one of those puzzles where making the puzzle is probably harder than solving it.

[finnv]

Watching a 25 minute sudoku video wasn’t part of my evening plans but I’m not complaining

[AgentMCCityDE]

Imagine wanting to solve a sudoku and suddenly being forced to know the rules of chess

[inspiringsand]

Rules: 00:49
Let's Get Cracking: 02:43
Puzzle Solved: 24:40
Simon's time: 21m57s

And how about this video's Simarkisms?!
Wow: 3x (11:36, 11:36, 14:22)
Bother: 2x (21:41, 22:16)
Obviously: 2x (01:32, 10:04)
Good Grief: 1x (10:38)
Eyes are Drawn: 1x (14:40)
Axiomatically: 1x (04:30)
Naked Single: 1x (21:13)
Clever: 1x (14:04)
Beautiful: 1x (24:40)
Fascinating: 1x (14:22)
Elegant: 1x (11:36)
Going Mad: 1x (20:26)
Hang On: 1x (11:54)

Most popular number(>9), digit and colour this video:
Fifteen (14 mentions)
Seven (50 mentions)
Yellow (2 mentions)

Antithesis Battles:
Odd (3) - Even (1)

[RebuildingSteve]

"That square is actually a naked single, that square is a 6"

Wow me and that square have a lot in common

[DavidErickRamos]

Don’t know how this ended up on my recommended, but enjoyed it from start to finish. Brilliant work!

[mymy]

"We've done all of the 2's all of a sudden... Wow... Wow... How elegant is that?" This guy is amazing!

[tylergerald]

At first when you were going over the constraints I was initially thinking "this is impossible" but they actually help you narrow things down, especially the knight's move constraint!

[aixan]

the pure adrenaline i felt when he started cracking off all the two's

[bryangomez]

I feel like the kid in high school who contributes nothing to the group project but still gets an A

[denitsar]

Man: solves whole sudoku and shows little to no excitement
Me: *figures out a number before him and is excited like a kid hearing the ice cream truck drive by*