How to SOLVE DIFFICULT SUDOKU with Coloring - SHC

[@wistyLMD]

Thank you so much for the feature! I love your solve path, it's been fascinating to see how different people approach this puzzle! Great recommendation for another video of yours, and a really nice quote from Democritus as well! Your channel is so refreshing :)

[@SmartHobbies]

Thank you so much for the kind words and for agreeing to take part in the setter spotlight series. Your Classics have a great style to them that truly set them apart.

[@alexanderstelmakh8906]

Could you please share your solving path? Does it include the Mutant Fish?

[@wistyLMD]

@@alexanderstelmakh8906 My solve path is much more of a global deduction than something like fish. The core of this puzzle is that we need to place a total of 12 low digits (1, 2, 3) into rows and columns 1 and 9 with r1c1, r9c1, and r9c9 counting twice. Of these low digits, we can only place one 2 and one 3 anywhere outside of box 5 in row 5 and column 5 combined, because of the empty rectangle in box 5. We can only place one of each low digit in box 3, and we can only place one 1 and one 3 in box 7. This means in order to reach 12 total low digits we need to maximize all of our 1s, 2s, and 3s in row and column 1 and 9, as many as can possibly be in all previously mentioned locations - r1c1, r9c1, r9c9, box 3, box 7 and the combination of row and column 5. This eliminates all of 1, 2, and 3 from elsewhere (outside r19c19 and box 5) in box 3, box 7, row 5, and column 5, which will reduce the puzzle to hidden and naked singles.

[@alexanderstelmakh8906]

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[@wistyLMD]

@@alexanderstelmakh8906 My solve path is much more of a global deduction than something like fish. The core of this puzzle is that we need to place a total of 12 low digits (1, 2, 3) into rows and columns 1 and 9 with r1c1, r9c1, and r9c9 counting twice. Of these low digits, we can only place one 2 and one 3 anywhere outside of box 5 in row 5 and column 5 combined, because of the empty rectangle in box 5. We can only place one of each low digit in box 3, and we can only place one 1 and one 3 in box 7. This means in order to reach 12 total low digits we need to maximize all of our 1s, 2s, and 3s in row and column 1 and 9, as many as can possibly be in all previously mentioned locations - r1c1, r9c1, r9c9, box 3, box 7 and the combination of row and column 5. This eliminates all of 1, 2, and 3 from elsewhere (outside r19c19 and box 5) in box 3, box 7, row 5, and column 5, which will reduce the puzzle to hidden and naked singles.

[@jand147]

I learned a lot from watching and doing the puzzle along with you. I love the logic. I especially thought the empty rectangle that did double duty was very insightful! The coloring logic is something I still need to understand a bit better but I will get it eventually. I still do Sudoku the old fashioned way- on paper. So I don't know in my case if I will be able to use the coloring logic. Thanks for the great teaching in this Sudoku!

[@SmartHobbies]

Thank you so much for watching and your feedback. I still do paper and pencil puzzles as well as online. Instead of coloring, you can try lettering (“a”, “b”, etc) instead of colors or circling candidates to keep track of the logic. Hope that helps.

[@jand147]

I will definitely try it with lettering. What a great idea! Thank you for sharing that! Now I'm going to rewatch the video and hopefully I will understand the coloring technique better.

[@SmartHobbies]

@@jand147 Sounds great. I hope you do!

[@alexanderstelmakh8906]

Why dont set 3 in r9c1 right in the beginning of the solve? Using empty rect on 1s in block 3???

[@wistyLMD]

This is a great spot! This is also the first thing I imagined the solver doing when solving the puzzle.

[@alexanderstelmakh8906]

@@wistyLMD wow! nice to hear ) And what are the main break? is it the same as in the video? or ?

[@wistyLMD]

@@alexanderstelmakh8906 i posted it above as a reply to your other comment!

[@johnhart1790]

Love the solve. Having solved the 3 in r7c8 you now know there is a 3 either in r5c7 or r5c9, which leads to a 3 in r4c5 or r6c5 solving the 9 in r1c5

[@SmartHobbies]

Quite insightful, John. Glad you enjoyed the solve. Thank you for sharing.

[@paulakeay4317]

I solved this before watching your video, and I think I used a kind-of fireworks technique on the 123. Really enjoyed this puzzle!

[@SmartHobbies]

Very cool Paula. I got another Wisteria video coming out later this month. Hope you enjoy it as much as this one.

[@AnonimityAssured]

I can't even start this one. It's so far beyond my capabilities that I'm not going to waste another second on it.

[@SmartHobbies]

It’s got some beautiful logic. I do promise at least 1 approachable puzzle by Wisteria this month:)

[@JohnRandomness105]

Doing the puzzle justice was beyond my capacities as well. Nevertheless, I tried and managed to mangle my way through, doing a haphazard job.

[@jimbobago]

How do you use these ideas with paper puzzles?

[@SmartHobbies]

Great question, Jimbo. You can do A/B marking in the corner of the cells to represent the different colors. Hope that helps. How long have you been watching the channel?

[@jimbobago]

@@SmartHobbies About six months. Been trying to solve sudokus (with various levels of success) for a couple of years.

[@BradJames878]

This puzzle came up in my recommendations, and it turns out I had never seen it before. I like this kind of puzzle because it's clever and you don't have to fill in every single cell with all candidates to be able to solve it. I still didn't solve it without help from the video though, but I had the knowledge to do so. I think I'm just not patient anymore and I click on the video too fast.

[@SmartHobbies]

Wisteria made some great puzzles for the channel, Brad. I’m glad you liked this one. I do appreciate you watch the video and comment. 🙌

[@JohnRandomness105]

I'm not sure what to say about this puzzle. I think I found the intended initial break-in involving 123s around (and near) the edges and corners. Once that happened, I didn't know what to do with a lot of 1X bivalue cells. I bifurcated a couple times, ending in a crash or finding digits in cells common to both choices. There was an X-wing in 2s. I managed a couple small chains, such as a 3 in one cell leading to a 3 in another that it could see. Overall, I did a haphazard job at this puzzle. 3:30 I used both 123 triples, but unfortunately, the empty-rectangle pattern in the middle block escaped my notice. I used the triples and column 9 to get rid of the 2s in R1C5 and R1C7, and the 1 in R1C7. 4:50 On the other hand, I didn't get rid of the 2 in R5C9 until far later, as a consequence of the X-wing. 7:40 Your next tactic, I think, is to use the string of 12 pairs to place the "3 in the corner". At least, that's what I did.

[@SmartHobbies]

Nice job with your solving. These puzzles are creative and challenging.

[@hansburch3700]

Ich mache Coloring mit Abzählen, immer eine gerade Nummer und eine ungerade löschen alles, was sie gemeinsam sehen.

[@SmartHobbies]

Nice. I have not heard of that. I know of some people who do letters. Thank you for sharing, Hans.