Step-By-Step Method For Hard Sudokus

[@thesundancekid123]

Obviously my problem is, that my eyes are not immediately drawn anywhere.

[@neilnolte2587]

Yeah, I'm looking but all I see are numbers.

[@Anonassassin]

😂😂😂😂 This comment. Tip my hat off, I with you on that brotha. This soduku puzzles have me feeling like I'm cracking the next Da Vinci code

[@brandyflowers2067]

Dude. Same

[@eldante4139]

How does he enter all the 6s in like ten seconds whereas I’m still getting my eyes adjusted to the puzzle 🤣

[@biaberg3448]

@@eldante4139 He had probably looked at it beforehand 😊

[@Blindpig14]

We need more of the step-by-step guides! Thank you.

[@Blindpig14]

Ahhh...the 7’s...I missed it - and that broke the puzzle for me! THANKS!

[@blandingswest6560]

Your solutions of hard classic sudokus continue to be the most interesting and helpful videos on the site. Scanning rows and columns in groups of three leads to a HUGE improvement in technique and accuracy. Hard sudokus (even those with hidden sets) used to take me 45 minutes to solve, but now they fall in less than 20. Admittedly you make it look easier than it really is, even though you are doing nothing magical. Perhaps it is only a matter of practice, which leads to greater confidence and ease.

[@Doc_Fartens]

More of this style of video please. I learned a lot from you taking it slowly and explaining every step rather than just assuming that everything you find is clear as day.

[@racoon_in_ankhmorpork]

I think that one just needs to solve an incredible amount of sudokus to gain the instinct that you have. As a newby, my eyes aren’t drawn anywhere in particular when looking at a grid and I struggle at spotting patterns (or even mistakes) sometimes, simply because I’m not used to it. I am confident that if I continue on with solving sudokus I’ll get there eventually, though, and that is largely due to what I have learned and continue learning from this amazing channel, so thank you!

[@DirtyOldMountainGoat]

In the Pacific Northwest (USA), there was a mountain climber by the name of Fred Becky. He had tons of first ascents and was one serious mountaineer. If you look at his climbing guides (classics and used by EVERYONE), he had a phrase when looking for routes. It usually went like this: "Find the obvious ramp" or variations thereof. The reason I am bringing this up is that the obvious for trained eyes is not the obvious for untrained eyes. Hence, my subscription to this channel. My hope is that by continual immersion in the "tricks of the trade", the once non-obvious ramp becomes the obvious ramp. Thanks for making the obvious, obvious.

[@peterdunlop7691]

In the About Us section in the scroll down bar, Mark is still listed an an eleven-times winner of The Times championship. Needs an minor update. Well done Mark.

[@qillerdaemon9331]

8:15 and 11:48 worth it just for those alone. Simply did not see them. I spent about four minutes solving a few obvious cells, and then a bunch of pointy and ghost pairs, then sat for over a half hour in self disgust. I'll be on the lookout for that kind of solution in the future. Thanks!

[@Wonderland_Jutomi]

Oh goodness gracious this one took me 70 solid minutes. The thing that cracked it for me was spotting that the 8 in the lower left box could only go in column 3*, and that took me maybe half an hour. Granted I'm not the greatest solver, but the fact that I solved it at all was a huge accomplishment. :)

[@Kingcob7]

Took me 18 hours 44 minutes. Don't fall asleep when you start a sudoku :D

[@Blubb5000]

What? You only slept for 34 minutes?

[@Pyromonkey83]

15:38, according to the times mentioned at the start of the video, I'm now an "expert" solver! That is 100% thanks to you two and this wonderful channel. 6 months ago, I'd have no chance to solve this puzzle at all, let alone do so with an "expert" time. Also, I loved the guest puzzle additions in the classic sudoku app, they've all been brilliant! Special tip of the hat to Derek Neal and Sam Cappleman-Lynes, who have produced some absolutely stellar puzzles throughout the app.

[@Aaron-cs3xl]

You're a full minute faster than me. I hope to be an expert solver like you someday! I will say though that this puzzle is definitely simple in terms of techniques, since it would take me a lot longer if there were any tricky techniques required.

[@glockdookie5231]

Ill pee in your urethra

[@gposchman]

I solved the puzzle myself. I had not thought of looking at 3 rows or columns at a time. Great idea, speeds up the solution. I found the 8s in column 3 sooner because of both squares above box 7 had 8s blocked. That allowed me to find the 5 in box 7. I am pleased with myself because I had found the triplet in box 1. Before I began watching you and Mark, I would have missed it. Thanks for a marvelous tutorial. I always learn something new.

[@timdunkley9173]

This is a perfect video for people new to the channel. Good, basic technique is vital and needs hammering home, just like Simon continues to do. Thanks.

[@ZmajevKralj]

88mins to complete. Feel like an absolute champion even though every other person here seems to have done it in under 20mins. This is the first one I've solved without hints or watching the video. What ultimately got me there (still haven't watched the video yet, I wanted to attempt it prior to watching it; so there's probably better advice on the vid!) was the improvement of my logical deductions. By working hard to find where you can place "Snyder" notations and looking everywhere you can to rule out where numbers can occur, you slowly but surely will get there.

[@HerveAttia]

video starts at 2:38

[@boorad99]

Does anybody else hear his voice in their head when they're solving Sudokus now?

[@zzcanasta]

Yes, but he's usually saying 'Look, just stop now. Stop. Now. Please.'

[@GiveupforJesus]

Sometimes I hear him say; "look at this column, where can a 6 go?" lol

[@thereoncewasalimerickwriter]

I can do a fair impression now, when things get tricky. Oh Bobbins!

[@iblivs21]

this feels comforting, knowing I'm not the only one.

[@jimhenry5552]

No, but I do find myself saying "Boggins" when I am confronted by problems in real life...

[@briangriswold6030]

I really appreciate the step by step puzzle solves you do. I’ve been watching for 3-4 years now and there are still common techniques I haven’t mastered. When you do a slow solve like this it helps to cement the basics!

[@tmnvsv7806]

Just want to say thanks. I've been following the channel for a month and went from complete novice to being able to solve the puzzles you post almost by myself. I still stuck few times during the solving, but the progress is huge! thanks again

[@Zylarlander]

Finished in 22:06! I'm pretty happy with that time. I've been having a string of solves from this channel at forty minutes.

[@peterdunlop7691]

I'm fairly new to Sudoku and I like your idea of starting in a group of 3 rows, then a group of 3 columns etc. I tend to start on 1 and then put in as many 1s and Snyder notation 1s as possible and then proceed up the numbers before restarting.

[@parka668]

Excellent video. I've always just done sudoku with the technique of just using big numbers to fill numbers in and had not started pencil marks. Struggled with hard sudokus and thought they were boring. Much much preferred Picross (nonogram) puzzles for my logic fix but these videos have opened my eyes to the beauty of sudoku puzzles. Amazing.

[@matthew456turner128]

Solved it in 24:50. Very very tricky. Hints were very well hidden. This puzzle is an example where you really need to be detailed with your pencil marks. I'm very pleased that I was even able to solve a puzzle featured on this channel😁 No first hidden skyscrapers for me though😃

[@Urroner]

Thanks for taking the time to plug through this puzzle and explaining in great detail the hows and the whys. Once you explained your reasoning on some of the things you do, I felt almost embarrassed for not seeing the obvious. You are Sherlock and I feel like Watson who can't see the obvious.

[@javeywavey]

I arrived at 5 for R1C9 (timestamp 11:45) with a relatively more straight-forward way. Obviously 1,2,3,4,6,7,9 are eliminated. This leaves 5 and 8. Since there are already pencil marks for 8 in R7C3 and R8C3, that makes the answer 5. Ah the beauty of Sudoku

[@inlumina_punctro]

Good one, thanks

[@rodneytopor1846]

This was the logic that blocked me, though it's straightforward one you see it or have it explained, and I agree that your reasoning is more straightforward than Simon's.

[@MuraliVajapeyam]

You uploaded this video on the day of my birthday, over 1.5 years ago :) This is indeed a great explanatory video. I had already seen many videos from Simon so when I tackled the puzzle, it didn't seem hard at all. Ok, I did take almost an hour but it was because I messed up at some point -- my real time would likely be around 30 mins. It certainly helps that the crackingthecryptic app has a lot of goodies, in particular both center and corner squares. I like to solve the New York Times sudokus but they are artificially "hard" because its interface only allows "normal" and "candidate", so I can't mix corner and center. I did cheat sometimes by opening the puzzle in two different browsers and using each technique in one of them, but these days I try to work on my perception and use what I learned here to solve the NYTimes puzzles while "handicapped". With the interface here I think most NYT sudokus would be straightforward. Without it, at NYT I always start, as Simon suggested in a different video, by pencil-ling every time a 3x3 box has a number that can only be in 2 squares -- today that is almost automatic. I still have a blind eye for naked singles, but working on it...

[@CommittingSudoku]

I've been doing like 3 hours of Sudoku for the last week, these puzzles are really addicting lol. Thanks to your channel, I've gotten a lot of practice with the basic methods and I'm feeling pretty confident atm since I solved it in 6:56

[@tbailey223]

Thank you for walking us thru strategy on classics. My puzzling has improved noticeably thanks to you two! God Bless.

[@hariman7727]

46 minutes, 35 seconds for me. While I was distracted, I was also struggling at multiple points to spot where restrictions gave me a new answer. . My breakthrough point was the 7 in box 8, as the placement of a 7 in Column 6 (r7 or r9) would conflict with other 7s, so row 9 column 4 was the only viable option. After that, it was a matter of eliminating squares where other numbers could go until the puzzle solved itself. EDIT: After watching the video, I'm quite happy with how long it took me to solve this one. I am nowhere near an expert, so being able to work though similar logic in a longer time makes me happy. :)

[@patricksmith3135]

You are indeed fast with these puzzles. I at new at them and only just getting to the 'hard' ones in puzzle books. I did learn a trick today so I thank you and I will continue to watch for you. Thanks again from USA.

[@TDMFAN]

Took me 16 minutes. I think I was only reasonably quick because I've done so many puzzles from this channel :)

[@_mnejing]

28:08. Took me a bit cause I paused for a few. Solved it after finding the 5 in box 7, that gave me a 4/5/9 triple in box 8. Essentially the same as your solve when you got the 7 in box 8, but just a different approach to the logic.

[@jdpjamesp]

Wow. What a difference 1 number can make. I had everything up to the 7 at 14:17 (col 4, row 9). And with that number the whole puzzle folded into place.

[@hariman7727]

Heh. It's a funny coincidence that the breakthrough point in the puzzle for me was spotting that exact 7. It still took me a bit to get through the rest of the puzzle, but that was the big sticking point.

[@cmonkey63]

In my journey to becoming a sudoku master (LOL), I am at the stage of acknowledging the power of pairs. This puzzle yielded to just that. Nice.

[@YallabinaConcertina]

"I love a pencil mark" oh, we all love a good pencil mark.

[@douglasmceachen4161]

But please stop calling me Mark.

[@bristolrovers27]

An excellent puzzle I good step by step video Since watching this channel my solving skills have improved greatly. Thank you

[@TheBrucemmoulton]

Even if it did take 40 mins I finally got one. Of course I wouldn't have until you pointed out my error in how to place 5 in row 1. Great lesson.

[@rabidsamfan]

12:26. Nice. Didn't need anything fancy, just persistence. Now to watch the vid.

[@elainelaw9464]

The first time I tried it I threw the book across the room. Now I'm addicted. The harder the better.

[@Keyboardje]

Did it on my own first, took me 21m 05s. Learned a lot by watching Simon do it soooo much easier and quicker after that!

[@mixiearmadillo7452]

This channel is great, and I'm learning a lot, but in videos like this I have to pause and do a lot of mini puzzles in working out his logic. Very valuable resource, just a series of brain teasers for beginners!

[@anphan9275]

took me 37 min to finish, take me long time to figure out 2 ER of 8 and 2 and after that just fill in blank cells easily. And after i see him spot a 5 in lower left corner with just those simple rules, very well technique there that i cant spot it out, i use pairs often than single pencil marks

[@ValeriePallaoro]

Wow!! Sniyder notation guy puzzle?? "Liked'" Difficult to crack??? You guys rock!!! Thank you so much, Abby for asking this question!!

[@anagramdk23]

Recently discovered your channel; it's a pleasure to watch you unwinding these beauties. Happy to subscribe.

[@edmundblackie6176]

edmundssf A most encouraging teacher: thank you!

[@BlueCyann]

I love puzzles like this one that don't need anything fancy but still aren't easy. It was really fun to solve, with the wide variety of techniques used, not just one or two.

[@kategeddon5307]

My time was 19:36, the first time in awhile I was able to finish without having to watch the video

[@Magetank4445]

As always, in awe. How Thomas somehow always manages to create masterpieces is beyond me! What a clever puzzle.

[@kayldee1215]

Me too, got to the last five numbers and found I made a mistake. Ahhhhhhh!!

[@RandomBurfness]

Fun puzzle! I completed this in 13:07. Not a brilliant time but I'm decently happy over it.

[@mbwchampion]

Took me 14 minutes and 29 seconds. :) Thanks for this video.

[@r0bw00d]

1:11:55 is my time. In column four I had a 37 pair along with C4,R2 being either 3 or 9. However, despite knowing that the pair was present, it took me forever to see that I could use the 3s in squares 1 and 5 to eliminate three as a possibility in C4,R2.

[@r0bw00d]

29:49 is my new time 8 months later. I'm not such a beginner anymore. (o:Þ

[@skullandcrossbones65]

G'day, It took me 45 minutes, I screwed up at one point and had to go back a bit.You do a great job explaining how you see the various clues.

[@kirknorman2403]

Really enjoyed this. It’s the first sudoku video that didn’t put me to sleep! Thanks🖖

[@azndeadman93]

I definitely learned something from this, especially at 11:05.

[@dylanerskine882]

Yeah I got really stuck on that one

[@Dabasin]

This seems like a very important logic to know. Just solving sudoku and figuring it out on your own (at least for me) would have taken hours

[@javeywavey]

I arrived at 5 for R1C9 (timestamp 11:45) with a relatively more straight-forward way. Obviously 1,2,3,4,6,7,9 are eliminated. This leaves 5 and 8. Since there are already pencil marks for 8 in R7C3 and R8C3, that makes the answer 5. Ah the beauty of Sudoku

[@kritav1111]

@@javeywavey Yup, got it the same way. Was wondering how no one saw that.

[@victorventurini1347]

I got the 5 as well. But I couldn’t understand why the number 2 could only be in the 2 upper cells... why couldn’t it be in the bottom cells too? Help

[@carrievandervort9142]

I’m new to the “hard” puzzles, so learning these additional techniques is helpful to solving them! Also, I’m old school - doing them on paper. It’s a lot cleaner on the computer!

[@iosifoulis]

25.10 as always ty for the puzzle. Took less time than i thought it'll take. Even though i use my own thick ways to solve puzzles i really do enjoy watching your ways of solving. Till the next one.

[@BlueCyann]

I'm almost the opposite. I use very similar logic to what Simon does, I'm just so. much. slower.

[@daveluttinen2547]

Great fun! Thank you. My granddaughter purchased a large Sudoku book and I'm not bravely going after the toughest puzzles in the book thanks to your help. I'm still wrestling with some of the clues you are so easily identifying, but every day reveals improvement. Would you consider marking level of difficulty on your headers so we can search out the easier or more difficult techniques we are looking for? Thanks, again, for the posts!

[@zipas]

made wrong assumption (which was right at the end) at 16:50 because of example at 12:13. otherwise wonderful video, ill definitely share it took me 19m55s btw

[@chaotix37]

20:08... I like these tips. Not bad. I appreciated more strategies like this.

[@keryngasparini3790]

Thank you so much for helping me with the really hard puzzles which I can hardly ever crack!

[@yasmin9510]

Nice sudoku! I did it in 20:28. I am a bit proud of myself. 😊

[@bddivine]

This was great. New to the channel. Picked up a couple new methods already. I live the pencil mark techniques. Made it easier my using them more selective

[@def3797]

What confused me was when he said Row 9, column 1 was a possible 5,2 and it therefore had to be a 5 as there was already a 2. But I saw that cell as a possible 5,8. Once I realized the 8s were restricted to column 3, rows 7 and 8 I could see how to get the 5. Unfortunately I had pencilled in five 8s in block 7 and it fried my brain until I realized the center 8s and the 8 in the corner cell were invalid. I am new to the game and pencil in too much.

[@joeroberson6676]

I wish HE had explained what you just explained as I had 8 as an option also and did NOT catch the restriction to column 3. So I really appreciated seeing your remark to explain to me what I had missed. THANKS!!!

[@topilinkala1594]

I solved this in about 5 minutes. I went back and tested what my solver does. It is instructed to stop when a decision is to be made. It did not stop. I single stepped it and it was "naked single", "hidden single", cleaning up, "naked single", "hidden single, "full house". "Full house" is that solver's way of saying that the number was optained by it being the only one missing from a row, column or a box.

[@csvidyasagar]

Sir, I am an admirer of your videos on Sudokju. The title of the videio is Step -By-Step Method for Hard Sudokus. My humble suggestion is you could have mentioned what are those steps. Say Step I is to locate same digits in two cells in the same block to place the same digit as candidates in the third block. Step 2 is to see what are the missing numbers in each row or column or box. The third step is to solve the puzzle as by that time most of the cells would have been filled.

[@EndlessMystify]

Took me roughly 25 minutes to complete, but I got stuck once and allowed myself to watch part of the video for hints.

[@The0rnate]

Really nice to see your solve as you went through the logic on this puzzle! I enjoy getting a look at your thought process and gives me some tools to better attempt to solve more difficult puzzles in the future.

[@argonwheatbelly637]

New techniques learned, I did. Delightful.

[@Robin19358]

Yes!!! Another puzzle by Thomas Snyder! (I can probably crack them if he makes them)! And a tutorial

[@morgangoering2986]

Love this style of videos. Would love to see you solve without telling us at first, just to see how fast you can solve it. Then wipe and show your logic. Just a thought. Also, I can't get enough of your channel. Since starting to watch I have now gotten my NY Times hard solves consistently under 10 minutes. :)

[@erikburman692]

Great, relaxing sudoku! Well done, Thomas :)

[@karlsangree]

Thanks for a great video. After binge watching your stuff for a couple days, I was able to bang this one out in about 43 minutes.

[@aryanshrajsaxena6961]

I am terribly high under medication, still solved in 49:14(took too long to see the 8 trick in box 7 due to high drowsiness). Will sleep now peacefully :)))

[@mathiasegeland1941]

Thank you for very clear methods for solving sudoku :)

[@BryanLeeWilliams]

45 Minutes. Yay. Nice y wing which after watching the video I didn't need.

[@eversleyowl]

You are a cracking teacher!

[@mydoggylives]

My time was 23:20.... but that's pretty good because I tend to do the Standard Sudoku puzzles and haven't pushed myself to do the Hard ones yet. 😁

[@JL-qo7cs]

This one helped me to improve. Thanks.

[@hamzahussain7794]

4:10 How does that 3 limit the 3 only into R8C5 and R9C5. Why can't it go into R8C4 and R9C4 as well? What am I missing here? I noticed that this very same 3 can give us a single 3 in the left middle block at R6C3. EDIT: Ah I see it now, he's talking about the column. The column can only have 3 in r8 and r9

[@lakarto19]

07:22 solve; although it would take me a lot longer in a traditional pen&paper setting, so it's not really expert-level, to be honest. Nice to see a nice, (relatively) simple classic sudoku, after several consecutive days of brutal variants. Personally, I think placing the 5 in row9column1 was the most important trick required to break the puzzle.

[@AWildBard]

11:16 I had to watch twice to get the logic of the 5 on the lower left. very nice

[@ol1ver49]

I did most of the second half differently with the same result. This was for me an endless series of triples begetting more triples, but fotunately I knew that technique before coming here,

[@insectbah]

Thank you for describing how you scan!

[@shahadalzarooni4653]

Is there more step-by-step videos? I really liked this video and enjoy this channel a lot

[@csvidyasagar]

Sir, You have almost 1700 vidoes. But as a learner of Sudoku, it is very difficult for us to graduate from Easy to Medium to Hard to Expert levels of Sudoku puzzles. My humble suggestion is if you could rearrange you vidoes to be Easy 1, Easy 2, Easy 3 and so on. Then Medium 1, Medium 2, Medium 3 and so on. Then Hard 1, Hard 2, Hard 3 and so on . Finally Expert 1, Expert 2, Expert 3 and so on. A beginner will not be able to understand anything about videos solving Hard and Expert levels. Let him master Easy puzzles first, then graduate to Medium puzzles and then to Hard level and finally to Expert level. Please consider this suggestion.

[@jamesseabury4394]

How come at the 15:15 mark in the video in column 9 the 4’s can only be in rows 4 and 6, what tells you that a 4 can’t be in row 5 in that column? I am having a hard time figuring out why the 3’s in column 5 in box 8 were placed before the 3’s in column 4 box 2?

[@joshjgordon]

51mins for me. It all fell into place once I spotted the 5 in the bottom left. A good traditional puzzle. Its good to have these mixed in with the more unusual variants.

[@rodneytopor1846]

I agree that the 5 in r9c1 is the (non-obvious) key.

[@ariel_haymarket]

21:39 with some tips from Simon - and my having come back to this puzzle with fresh eyes.

[@normanbray3381]

My program took 4 mins 23 secs to solve this. Its the logest time yet on a puzzle. Thanks

[@ziziorens348]

Nice, got it in 26:19!

[@freddiehand6551]

Naked singles where one of the possibilities is ruled out indirectly (e.g 12:30 where R9C1 could be a 5 or 8 looking purely at digits in the grid but cannot be an 8 because 8 is already fixed in one of R7C3 and R8C3) are one of the hardest elementary techniques to spot. I can never see them quickly!

[@scottjacoby2594]

Freddie Hand i was scrolling through the comments trying to figure this out. I can’t quite follow the logic on this one.

[@BlueCyann]

@@scottjacoby2594 I don't think Simon's approach was the most easy-to-explain way to look at it. There's other ways, though. At root, it's simply that none of 1,2,4 or 8 can be in the lower left cell of that box (and 3,6,7,9 are in there already), so it has to be a five. I think Simon was trying to demonstrate the more general idea that, if you have every single number EXCEPT ONE entered into or pencil-marked into a box using Snyder notation (his corner markings), then any cell with only a single pencil-mark can only be that number OR the number you haven't pencil-marked yet. In this case, it led him to note that he hadn't pencil-marked a 2 into that box yet but had marked everything else; the lower left cell therefore had to be 2 or 5; and oh hey, there's already a 2 in column 1.

[@scottjacoby2594]

BlueCyann but can’t an 8 fit into R9C1? I don’t understand Freddie Hand’s logic.

[@rabidsamfan]

@@scottjacoby2594 It can't, but the reason it is eliminated is because of where the 8s can go in column 3. You see, once you've determined that the 8s in column three have to be in the bottom left box, then you cannot have an 8 anywhere else in that box. This uses array logic (the stuff Simon notates in the corners) to determine how to eliminate possibilities in the cells (the stuff Simon notates in the center of a cell.) Whenever you have a conflict between a digit that has been placed in a pair by array logic and a candidate of that same digit in another cell in the same box, the array logic wins. It's a little like what happens in the bottom central box, where we can determine that the 3 mus appear in column 5 . That means 3 can be eliminated in row 9 from the cells in column 4 and column 6. Does that help?

[@scottjacoby2594]

rabidsamfan I still didn’t quite follow, but I took what you said about determining the 8s were in C3, i looked back up at the puzzle to remind myself why he marked them. And because the only other “blank” in C3 is R4 which is pencil marked with 1 and 2 that the 8 must be in either C3R7 or C3R8, eliminating C1R9. So that part helped lol

[@railwaymaniac]

12:10 onwards. Can someone please explain why the 2's cannot be in row 8 of box 7 ??

[@mata2723]

I love the "sorry, I was quite slow....". Took me 56 min as I didnt see the 7 in the bottom and had to pencil mark everything...

[@glennmelven3414]

The key to this was spotting those naked singles in the corners. Without seeing those this puzzle took me almost 45 minutes.

[@AnigameLover]

I still need a long time to spot single hidden digit. I still need a lot of practice

[@Fogmeister]

Hmm... I thought I'd have a go at this... I got stuck. :( I did spot some using some techniques that I've picked up watching your videos but I just got to a point where I couldn't get any more information out of it. OK, I got to where you were at 8:53 I got the two 5s (although it took a lot longer) but coudn't get anything after that. OK... as soon as you mentioned the 8 (which I had already used and pencil marked). I then was able to make the immediate conclusion myself that gave me the 5 in the bottom left corner. That broke open a lot of the puzzle for me.

[@Fogmeister]

Finally done it! Thanks, that comment about the 8 in column 3 did it for me. Even though I didn't watch after you mentioned it. I had already pencilled in the pair of 8s in the bottom left box. The rest just fell into place.

[@Fogmeister]

Just watched on a bit more. The logic you mentioned at 11:48 is what I was missing. I got there by myself but it took me far too long. :D

[@qaissindy1]

Thanks, but, I don't understand why at the minute 12:15 you marked that square 2and 4. it supposed to be2,4 and 8. I am little bit confused. would you please explain.

[@arthurbaumann7106]

Can somebody please give an alternative explanation of the trick at 11:05 ? It's not clear from Simon's explanations.

[@rabidsamfan]

Simon is depending on the marks he's already placed, but he's already internalized the understanding of how he placed the 8s, and how that operates on the rest of the box. It's easy to see that if you can limit a digit to two (or three) aligned cells within a box that intersect with a single row (or column) that will eliminate all instances of the digit in the rest of the row (or column). It's not quite as instinctive to recognize that if you limit a digit in a row (or column) to two (or three) aligned cells in a single box that eliminates all other possible positions for that digit in the rest of the box. So in this instance, he'd found the restriction for the 8s earlier (about 9:25) , and can see that he's also he's restricted 1, 4, and 5, as well. He's got 3,6,7, and 9 as given. He needs to find out where the 2 can go. There's a 2 in column one, which is the only restriction. So, if he were placing the candidates in the centers of each cell in the box he'd end up, reading across then down with 3, 24, 28 in row seven; 7, 124, 128 in row eight, and 5, 6, 9, in row nine. (Incidentally, the principle of restricting on column (or row) limits the box possibilities also applies to the 3s in the bottom center box/column five.)

[@arthurbaumann7106]

@@rabidsamfan Thank you, took some time to wrap my head around it but I finally got it !

[@rabidsamfan]

@@arthurbaumann7106 you're welcome!

[@HenkieHeadache]

I'm lost @ 14:16 with your choice of 7 in that place. 7 can also be in the upper square on the left (with the pencilmarks 3).

[@alf10087]

1:42:54 - For a moment there I though I was lost, but got the handle of it even if it took longer than it should've.

[@erikhauge9034]

You don't need pencilmarks to put the "5" in the corner at 12:33. You know that the "8" must be in the trird culumn i the box. Then the "5" is easy to place.