The Astonishing Deduction

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** TODAY'S PUZZLE **
After yesterday's incredible puzzle from Phistomefel, we showcase this sudoku called '2many arrows spoil the box' by tesseralis. This features one of the most remarkable and original deductions we've ever seen.
You can try it at the link below:
app.crackingthecryptic.com/su...
Rules:
Normal sudoku rules apply. Digits along an arrow must sum to the digit in that arrow's circle. Cells separated by a knight's move (in chess) cannot contain the same digit.
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[@tesseralis]

Thanks for featuring this puzzle! I knew from the moment I set it "oh, Simon would love this!" 😊 You're absolutely correct that I set it to showcase the logic in box 5 and the puzzle is intended to fall apart after that -- much like a classic! You explained the logic perfectly and cleanly, as always!

[@meaninglesscommenter8457]

HI, Bug here, thank you for the birthday shoutout!! My friend has begun mastering sudokus herself :D

[@joescarborough1]

"Let's abandon all this" triggered Alexa. Let's a misconstrued as Alexa.

[@penningmeestercgkdelft9159]

Hi Simon, if you prefer to give consistent names to groups of adjacent cells based on what one usually uses, it is heptomino indeed, I would say! So then we'd have monomino, domino, triomino, tetromino, pentomino, hexomino, heptomino, octomino and nonomino, or generally polyomino, which are forms that all come from ancient Greek. When googling for "polyomino" you'll often find this result. On the other hand, the nouns triple, quadruple, quintuple, etc. are based on Latin forms.

[@davidhyams2769]

"Let's try the knight's move constraint" Looks at the 1 and the 2, without making any progress. But then for some reason, Simon's grasshopper mind ignores the 9, which would have eliminated 9 from the arrow totals in r3c3, r3c6, r5c3 and r5c6. So the 9 must be either r7c3 or r7c6. Without colouring!

[@tyrgannusgaming6657]

They're usually called heptominoes. You can blame our months for making it confusing!

[@lomax343]

Am I the only one who kept asking "What does the explosion mean?" before realising it's made up of seven arrows?

[@CapKhoury]

Rotational Symmetry! The finished grid is fixed by the automorphism that rotates the grid 180 degrees, fixes 1, switches 2 and 6, 3 and 7, 4 and 8, and 5 and 9. Fancy putting that in an arrows puzzle. So clever.

[@judithcabanero]

And 2 many text spoil the sudoku title

[@TheSpazattack540]

Anyone else have a minor stroke watching Simon colour the middle box and the completely ignore his colours and try to work out the digits by brute force?

[@RolandGiersig]

I find it very interesting and funny that Simon in at least two instances spotted the knights move constraint before the straight Sudoku constraint. 😁

[@michaelbellecourt3875]

Last night, as my fever kept me awake, I found myself contemplating pentominoes, hexominoes, and even considered the fact that a Sudoku line/column/box is really just a nonomino.

[@showingthelinks8441]

The feeling of screaming "Sodoku" while knowing you would have never made it far enough to see the sodoku logic.

[@inspiringsand123]

Rules:

[@user-cf2ki3mw3b]

The idea of the phistomefel's ring was not actually useless

[@Gonzalo_Garcia_]

17:02

[@emilywilliams3237]

This was a fantastic puzzle. It's one that I took at look at before watching the video and in truth might have been able to do it myself, but decided that I would get more pleasure from watching Simon solve it. Indeed, it was great, Simon. Thank you!

[@lauracortes7720]

just got the notification that my book shipped! :D

[@Orenotter]

How wonderful hanging with y'all is.

[@wanderlustwarrior]

27:05