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Old 05-22-2020, 01:47 PM
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The Miracle Sudoku: 'the most riveting video Iíve seen all year'


I never thought I could ever watch a full 25 minute video of a guy solving a sudoku puzzle... but I watched the whole thing right through without my attention wandering for a moment, and it seemed like 5 min.

Article:

Puzzled man solving 'miracle' sudoku becomes YouTube sensation

Video:

The Miracle Sudoku
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Old 05-22-2020, 06:20 PM
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I'm already confused. The text on the side says "Any two cells separated by a knight's move... cannot contain the same digit." Uh, why not? When did they invent that rule?
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Old 05-22-2020, 07:08 PM
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I'm already confused. The text on the side says "Any two cells separated by a knight's move... cannot contain the same digit." Uh, why not? When did they invent that rule?
It's not a universal rule - it's a special rule for this particular Sudoku that makes it challenging and miraculous.

Thanks for sharing, OP. I don't really get Sudoku, and I thoroughly enjoyed it. I just sent the link to my Dad who is a big Sudoku fan.
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Old 05-22-2020, 07:10 PM
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Yeah, it's sudoku with special rules. It's the only way you could ever solve something with only 2 starting squares filled in, I suppose.
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Old 05-22-2020, 07:11 PM
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I'm already confused. The text on the side says "Any two cells separated by a knight's move... cannot contain the same digit." Uh, why not? When did they invent that rule?
Quite a while ago. It's one of many variants of Sudoku. Others include Killer Sudoku, where along with normal rules, there are "regions" whose digits sum to a given number; Thermal Sudoku, where there are sequences of digits that must increase monotonically; Sandwich Sudoku, where the sum of the digits between the 1 and 9 in each row/column are given; and many others.

You might think that these restrictions make solving harder, but they actually make it easier (since any restriction reduces the number of possible digits in a given cell), so to compensate, fewer starting digits are given. Hence the answer to your question, "Uh, why not?" is that with only two digits given, there would be no unique solution without that rule.

Last edited by TonySinclair; 05-22-2020 at 07:13 PM.
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Old 05-22-2020, 08:18 PM
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Quote:
Originally Posted by GreenWyvern View Post
I never thought I could ever watch a full 25 minute video of a guy solving a sudoku puzzle... but I watched the whole thing right through without my attention wandering for a moment, and it seemed like 5 min.

Article:

Puzzled man solving 'miracle' sudoku becomes YouTube sensation

Video:

The Miracle Sudoku
Yeah. It was a lot of fun to watch.
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Old 05-23-2020, 02:34 AM
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I've actually been watching this channel for several months. Simon's excitement when he starts breaking through on a puzzle never fails to make me smile, though his reactions are usually not quite as exuberant as in this particular example. I did actually solve this particular puzzle before watching the video, and found it quite fun. However, it turns out that mathematically there's only one real solution to a sudoku with these restrictions - any variations are just transpositions of that same solution, and all the given digits do is eliminate the ambiguities of which transposition you're dealing with. The sequel puzzle they put up a few days later was, in spite of being a little more difficult to get started on, rather less satisfying to solve because it was obvious how it was going to play out once you found the first few moves.

If you like these sort of puzzles at all, their channel is well worth following if only as a steady source of well-constructed puzzles that you don't have to worry about getting stumped solving because you can always watch the solution.
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Old 05-23-2020, 06:04 AM
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Nice video.
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Old 05-23-2020, 08:24 AM
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What other constraints did this sudoku follow? With any set of rules based only on digits in particular squares not matching, you still need at least 8 squares filled in at the start. If this one really only had 2 squares filled in at the start, then it must have had some other kind of constraint.
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Old 05-23-2020, 10:31 AM
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The Miracle Sudoku: 'the most riveting video I’ve seen all year'


Quote:
Originally Posted by GreenWyvern View Post
I never thought I could ever watch a full 25 minute video of a guy solving a sudoku puzzle... but I watched the whole thing right through without my attention wandering for a moment, and it seemed like 5 min.

Article:

Puzzled man solving 'miracle' sudoku becomes YouTube sensation

Video:

The Miracle Sudoku

Pretty incredible. I’m a Sudoku fan from way back, and this guy’s process of deduction is very intriguing to watch.

Last edited by Biffster; 05-23-2020 at 10:31 AM.
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Old 05-23-2020, 11:00 AM
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Watching this video, my journey paralleled his.

"There's no way a video about a dude doing a Sudoku puzzle could be entertaining. I'm going to turn it off in just a minute. Having said that..."

Really cool video. It's often entertaining to watch somebody who is passionate and excited about an activity even if the activity itself isn't exciting to the viewer. Thanks for sharing!

Quote:
Originally Posted by Chronos View Post
What other constraints did this sudoku follow? With any set of rules based only on digits in particular squares not matching, you still need at least 8 squares filled in at the start. If this one really only had 2 squares filled in at the start, then it must have had some other kind of constraint.
In addition to the normal rules:

Any two cells separated by a knight's move or king's move cannot contain the same digit.
Any two orthogonally adjacent cells cannot contain consecutive digits.

Last edited by Johnny Bravo; 05-23-2020 at 11:02 AM.
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Old 05-23-2020, 01:44 PM
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Amazing video! Like the OP said, the time flew by. That guy is a brilliant solver.
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Old 05-23-2020, 02:37 PM
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Quote:
Originally Posted by SpoilerVirgin View Post
It's not a universal rule - it's a special rule for this particular Sudoku that makes it challenging and miraculous.

Thanks for sharing, OP. I don't really get Sudoku, and I thoroughly enjoyed it. I just sent the link to my Dad who is a big Sudoku fan.
That was fantastic. Thanks for sharing!
  #14  
Old 05-24-2020, 08:18 AM
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Ah, then the two given squares must have been a 3 and a 7.
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Old 05-24-2020, 08:56 AM
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Ah, then the two given squares must have been a 3 and a 7.
1 and 2
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Old 05-24-2020, 09:21 AM
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What a clever idea. I watched the first few minutes, then set off to solve it. It took me ninety minutes...then I watched the rest of it, amazed at how easy he made it look.
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Old 05-24-2020, 01:26 PM
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In addition to the symmetry that Mitchell Lee describes, this particular puzzle is also what I like to call a “Golden Sudoku;” the combinations of numbers that make up the 3x3 grids that make up the rows and columns of the puzzle contain the same combination of 3 digits.

The top row of three 3x3 grids for example uses the combinations 483, 726, and 159. If you look closely you will find a similar pattern of three digit combinations in rows and columns throughout the puzzle. Pretty cool.
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Old 05-24-2020, 02:30 PM
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Ah, then the two given squares must have been a 3 and a 7.
Is there some reason you don't want to just click the link in the OP and see the puzzle?
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Old Yesterday, 11:35 AM
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I just watched it, amazingly fun. The moment at 6:02 where he says "Although having said that" is the absolute best.
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