The Hardest Sudoku... And How To Solve It

You can try the puzzle you voted for, Hidden Clone by Sam Cappleman-Lynes from the UK Sudoku Grand Prix, here:
The test is available here:
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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

[pozxyyy]

I really wonder how I can just sit here and watch this guy solve a sudoku for half an hour, and be intrigued the whole time.
Great stuff

[wonderbop]

I want him to do one of these puzzles with the eye trackers on the screen

[mitch-lawless]

“I am lost in admiration”, what a beautiful and endearing sentence.

[riyo.]

The structure of this Sudoku is so insanely perfect. You're sat there, wondering during the whole solving of the Sudoku, if your approach was correct or not.
It's like watching a movie, where the main character follows calculated assumptions and you as the viewer, are always second guessing him. He gets hints all the way, which seem to lead him nowhere, right until the end, when his first guess, with the final piece of evidence, comes true and the whole case resolves, like a perfectly put together Swiss watch, with all the gears fitting perfectly.
It's just brilliant.
Mind blowing, how this is solvable and even more mind blowing, if you think about the fact, that someone has put this together.

[crhulsey]

this is far beyond me i like Sudoku but i have never searched google or youtube and some how this is on my Recommended page. lol great job

[OddSauce]

I think it's safe to say this quarantine is getting to me

[Animefan]

it´s 1.16 am.
On a tuesday
I´ve never tried a sudoku in my entire life.
Yet here i am. Quarantined and drunk. Watching this guy solve sudokus on 1.75x .

[KurtHugoSchneider]

incredible puzzle, managed it in 23:13 and I felt like I moved pretty quick.. absolutely crazy that the top people are solving this in 10 minutes.. too good

[agentg]

Go to 13:17 man that was the most British thing I’ve ever heard

[jumpingjflash]

I'm fascinated by all the features you have in your software:
1) the ability to mark and write in multiple squares at once
2) you have 2 types of pencil marks, centre and corners
3) the ability to shade squares with different colours
What app are you using, and is it available to download?

[brodhax]

I have no idea what hes talking about. Im just sitting here listing to smartness in action

[Ruminations]

I don't know how I stumbled upon this video - it's been many years since I last did a Sudoku - but I figured I'd give it a try.
Took me 1 hour 16 minutes 17 seconds. About double the times some of these other comments put down, but considering how long it's been since I've done a Sudoku puzzle, I'm still pretty proud. This was certainly a challenging one.

[smeutr]

The algorithm suckered me in with one video, and now I’m hooked

[hilcovanbreeschoten]

1:13:12 That took a very long time. Even getting an idea how to even start took me like 10-15 minutes. It involved a lot of new logic for me, and I'm very happy I solved it without resorting to the video.

[ardemus]

I enjoy the logic for translating the shaded region: You can't translate more than 2 squares in any direction without leaving the grid. You must translate in both X and Y to avoid row and column duplication. The rest comes down to moving every shaded cell into a new region. Four of the shaded squares are in the corner of an outside/middle region. They can't move 3 spaces to cross the far boundaries, so they must all cross at least one near boundary. That forces either up/left or down/right. Finally, you must move 2 squares in both X and Y so the four central shaded squares escape the central region.

[Lorefall]

When your trying solving a puzzle and you cant even understand the rules, your in trouble.

[ainsleemcnamara]

"I wanted to explain that slowly... for myself" what a mood

[baccarah]

Im sure this guy can guess a girls phone number by just beeing given 2 digits.

[theknewwon]

This was the first non-traditional Sudoku that I was able to complete from this page without any help from the video! It took me 1:31:48 (which is insanely slow in comparison), but it's an achievement for me nonetheless. The logic behind figuring out how to clone the region was so amazing to figure out. Thanks for sharing these puzzles. I never would've thought about Sudoku with outside constraints if I hadn't found this channel!

[vesanius]

I don't have the patience to do sudokus myself, but watching this videos is just so relaxing for some reason. It's very easy to follow up and even as an amateur I still understand the reasoning behind everything because it's all well explained. Wathing this for sure will improve you as a sudoku maker as well. Not in a million years I would've thought that I'd end up watching a guy solving sudokus and never skipping a second and hours at a time. Genius.