Learning to solve Hard Sudoku

Normal sudoku rules apply. Each row, column and 3x3 box contains 1-9.

Akash's book is available as a paperback on Amazon. Here is the link

▶Our merchandise (including birthday merch) is here: ◀

▶ CTC FAN DISCORD SERVER◀


▶ OUR PATREON PAGE – JOIN THE COMMUNITY, SUPPORT US AND TRY OUR PUZZLE HUNTS◀

▶ OUR BACK CATALOGUE – ALL CATEGORISED WITH LINKS!◀

Miracle Sudoku is available on Android, Steam and App Store.

▶ THERMO SUDOKU is available too!◀

▶ TRY OUR CHESS SUDOKU APP◀

▶TRY OUR CLASSIC SUDOKU APP◀

▶TRY OUR SANDWICH SUDOKU APP◀

▶SEND US PUZZLES TO SOLVE/CONTACT US◀

▶FOLLOW US◀
Twitter: #crypticcracking
@crypticcracking

▶Music◀
Tim McCaskey plays Mozart's Sonata no 16 ("Sonata Facile")
▶SOFTWARE◀
Play the puzzle in the video by clicking the link under the video (above). Thanks to Sam Cappleman-Lynes and Sven Neumann for their work.
▶Logo Design◀
Melvyn Mainini

▶Opening Credits Design◀
Joel Blundell
▶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

[glennmelven]

I really liked how Mark showed the logic from the solver at the end.

[bakpaopuz]

How nice of you to pick one where I got absolutely stuck, haha.

Great solve, and thank you for the kind words :) Definitely recommend anyone interested in classics to get this book - not all of the puzzles are this challenging but they are all of exceptionally high quality. I had a lot of fun test solving all the puzzles.

- Chiel / bakpao

[akashdoulani]

Thanks so much Mark for covering this sudoku on ctc. You were amazingly fast on this. Very nicely explained. Btw, my name is wrongly mentioned as Akash Jain where you have provided the link to online solving :)

[JacobDGoldman]

At this point, I'm just happy I made it to the same spot and noticed the 1-7 pair when I got stuck. Maybe someday I'll be able to notice Y-wings or ask better questions to go further! (Definitely better than before watching the channel & starting the apps! 😁)

[jensbaumeister]

17:33 – which is a stellar time for me, as I'm normally very much on the slow side. Didn't use any special techniques, though. Just classic Sudoku elimination and naked singles.

[Coyotek]

Found the solution in a time of 11:10 ... but I guessed at r8c8 to get there. After my solve, I tried my other possibility; the puzzle broke shortly thereafter, but I didn't find a 'logical' path to get there. [EDIT - Mark did the same thing I did; I don't feel so bad now.] :)

Tough classic!

[BillLamoreaux]

I appreciate seeing different solve styles. You do you, Mark!

[williamgreer]

18:31 for me, I like how r1c9 interacted with box 9 and box 1 to cause problems in box 7

[craigroberts]

11m 43s. Finished today’s puzzles and went back looking for any I missed in the past and found this one. Pretty happy with the solve, I’m usually bad at classics.

[Daihatski]

Tried this puzzle.
Got absolutely stuck at the "tricky" part and could not find a solution for the life of me.
Ended up writing canditates into everything, but didn't help.

Trying to train spotting those chains but they are just beyond me.

Anyway. Great solve and great video as always. :)

[astewart]

I felt reasonably pleased with having solved this one in 36:33 while eating dinner and listening to the radio, until I saw the video... I did not remember using any clever logic, so rewound and and found I had made a mistake in logic that put a 1 in r3c9 when r2c9 was still a candidate, and as in fact this was a lucky guess, plain sailing from thereon. At least now I appreciate my failures more, at least then I backtrack and find the mistake. It makes me wonder, I have completed many puzzles correctly, but now I need to get to the next level and be sure I have actually solved them!

[alexklotz]

A few videos ago I mentioned the shift number pad bug, just noticed it's been fixed! Awesome.

[Wecoc]

8:06 - 10:06 What he found there (using coloring with a long chain) is a Grouped Discontinuous Nice Loop, following that path it's the only hard step required for the solve.
There are alternative ways to solve the puzzle with steps that are still hard but easier to spot, but more than one is required in that case.
16:09 - What he described here is an XY-Chain.

[emdes]

Lots of time spent looking for solutions, but my 33:34 time (with no mistakes) is good for me. Definitely improving watching this channel.

[RicardoRibeiro]

Thanks Mark for showing the alternative solution at the end. I am always in awe at the speed that you can read the numbers? How can you spot the 5/7/8 triple in 2 seconds?

[bernierossi]

12:07, I think my best solve yet. Did I just get lucky or am I on the improve?

[laszloliptak]

Nice puzzle. Solved it in 27:24. I am proud that I was able to find the logic Mark mentioned at the end :)

[wanderlustwarrior]

38:38 I was focused on r1c9 for a while, so it took me some time to spot that r9c9 was my break in.

[Frie_Jemi]

I've recently watched a few episodes of a series called McDonald and Dodds, I didn't realize at first why it was so appealing until just now making the connection that my favorite character on the show, detective Sergeant Dodds, reminds me of a combination of Mark and Simon. I hope no one finds this offensive, and I'm curious if anyone else agrees. On the show his deductions are brilliant and he is by far my favorite character.

[guanyin]

The 1 and 7 in box 9 forces a 1/7/8 triple into row 9 in columns 234. It forces a 5/6 pair into row 9 in box 9. The 5 in box 6 disambiguates the pair and the rest of the puzzle is somewhat easy.