These PROVEN Strategies Can Solve Hard Sudoku - SHC 248

[@SmartHobbies]

📕Get my FREE Solving Guide that will help you solve over 80% of all Sudoku puzzles🧩to include NYT Hard👉👉www.buymeacoffee.com/timberlakeB/e/125822 Timestamps 0:00 Intro 00:16 It’s Solving Time 00:29 Puzzle Story 01:04 Solving The Middle 02:04 BONUS Tip 05:56 Finding Snyder Restrictions 07:53 Setting Up Advanced Strategies 09:17 Proven Strategy #1 12:19 Proven Strategy #2

[@Bondye]

Great solve! W-wings are one of my favorite techniques.

[@SmartHobbies]

Me too! Great puzzle, Bondye. I am glad I got to share this with my viewers.

[@robertrisk93]

That 1-6 W-wing not only prevents r9c9 but also r1c1 from being a 1. So immediately you can solve r1c1 for a 3. I found another strategy before seeing the 1-6 W-wing. An X-Y Chain that solves r2c8 for an 1 (so r2c2 is an 8). The cells that form the chain are r3c2(56), r6c2(35), r6c8(39), and r8c8(89). If r3c2 is 6, r2c2 is 8 because r7c2 becomes 1. if r3c2 is 5, r6c2 is 3, r6c8 is 9, r8c8 is 8, and r2c8 is 1, so r2c2 is an 8.

[@SmartHobbies]

Perfect. Thank you for pointing that out, Robert!

[@tehcanadianbacon314]

In response to your question about my next move after exhausting Sneider notation - I scratched my head, tried to make sense of the world, and then pressed play on your video to figure out what I was supposed to do lol.

[@SmartHobbies]

Awesome 😃 Whatever works. I am here for you until you stop getting stuck on puzzles like this.

[@AnonimityAssured]

Colours and a UR made light work of this (13 = row 1 column 3): 13, 15, 25, 34, 55, 36, 95, 85, 74, 76, 54, 64, 44, 66, 46, 56, 23, 93, 73, 98, 42, 71, 89, 82, 52 (easy up to here, but then…), 21 (colours from here; or 2-String Kite), 37 (UR, boxes 3 and 6), 99, 48, 49, 38, 91, 72, 11, 62, 61, 51, 68, 39, 87, 88, 17, 22, 12, 28, 19, 79, 78, 59, 58, 97, 31, 32. Alternatives to the UR were various short chains. For example: 91 instead of 37 (1 or 6 in R1C9 excludes 1 from R9C9), 72, 11, 62, 61, 51, 68, 87, 88, 17, 22, 12, 28, 79, 78, 59, 58, 19, 97, 99, 48, 37, 49, 38, 39, 31, 32. Now to watch how I should have done it.

[@SmartHobbies]

Nice job using colors, Julian.

[@vidyanandsinha8879]

W wing Thank you

[@SmartHobbies]

Nice job! Thank you so much for sharing.

[@JohnRandomness105]

I missed the two-string kite and the W-wing. Once I had half (a third?) the digits placed and the rest of the cells centermarked, I was stuck of course. R1C9 and R9C1 both had 16, and I wanted to see how they compared. Easy: showing that if R9C1 = 6, then R1C9 = 6. What happens when R9C1 = 1 was altogether different. I couldn't keep track in my mind, so I cornermarked digits with this assumption -- my standard first stage in bifurcation. I went through almost the entire grid to get if R9C1 = 1 then R1C9 = 6. That got me R1C9 = 6 and R9C9 = 7. (Focused on those cells, I didn't place R1C1 = 3, but it didn't matter.) The rest of the grid unraveled. 1:50 With many five-digit houses, I began (after placing the 2) centermarking those houses. Progressively more developed. 7:30 At this point, with the same digits placed, I finished centermarking the grid. 9:30 Of course, the one time when I skip going through every digit to see how they are distributed, I miss a *productive* finned X-wing. The corner 1s and R1C2 remove 1 and place 7 in the green cell. 13:50 There's your chain, and there's my chain. Alternatively, R9C1 = 6 leads to R9C7 = 7, leading to R9C9 = 1 and R1C7 = 6, emptying R1C9. (I guess this would be called a hidden void.)

[@SmartHobbies]

Your chain also worked, John. I like hearing how people approached this puzzle by Bondye. I had so much fun with it.

[@anaayoung9142]

My time was 11:00 great time! 😅 I did this one alone, finally. I pencilmarked everything then what I saw: if R1C1 is a 7, rhen we have a 56 pair in box 1 making R3C7 a 7, and R9C7 a 6, R9C1 a 1 so R1C1 is a 3. Then R5C1 is a 9 and I found a triple in column 9. Before this I find some xy wings. The way you solved was easier and harder at the same time! 😅 Thanks for this! =)

[@SmartHobbies]

You are welcome! Nice job figuring out the restriction with the 7. Have you solved puzzles with W-Wings before?

[@anaayoung9142]

@@SmartHobbies Not sure. I don't remember the names. 😅🤗

[@vidyanandsinha8879]

Very hard Thank you

[@SmartHobbies]

Glad you liked it!

[@indigobunting2431]

Seeing is hard for me!

[@SmartHobbies]

You can do it! One cell can “see” all other cells in the respective row, column, or block. If 2 cells in are in different rows, columns, or blocks, then they will have at least 1 cell they can both see. Does that help?

[@chucklindenberg1093]

Wouldn't it be easier to say that if there are 2 conjugate pairs in opposite corners of the puzzle for instance r1c9 and r9c1 of the puzzle the opposite corners r1c1 and r9c9 can't be any of the numbers that make up the conjugate pair? Therefore r1c1 could only be 3 since it sees a 1 from either corner, and r9c9 could only be 7 because it sees both 1 and 6 from either corner.

[@SmartHobbies]

Great point Chuck. I should have pointed out that the 3 can be solved in R1C1 immediately due to this pair. Thank you for pointing that out.

[@robertrisk93]

That is indeed a two-string kite for 1, so r1c2 can't be a 1. There is another strategy that lets you come to that conclusion too. On c2 and c8 there is a finned X-wing for 1's, so r1c2 can't be a 1.

[@SmartHobbies]

Nice job finding the Finned X-Wing. Do you tend to see those before 2-String Kites?

[@robertrisk93]

@@SmartHobbies I generally look first for X-wings. I never really understood Finned X-Wings, but a couple of weeks ago, by revisiting one of your posts, I finally learned to understand them. So I found that one rather easily thanks to you.

[@SmartHobbies]

@@robertrisk93 Nice job, Robert! Thank you for sharing.

[@nayfen5767]

Since your goal is to make people learn, you should aim to use the right terminology in your videos. Why saying "conjugated pair" instead of strong link ?

[@sharmilisharmili472]

BTW , Both are correct, it is noticeable that he uses all synonyms, in terms of link it is strong link otherwise a conjugate pair, I think you hv missed his previous videos, you shd appreciate that he gives a detailed explanation and often tries to repeat things for the newcomers.

[@SmartHobbies]

Thank you for your comment. I agree that I should strive for correct terminology as much as possible. I tend to use the term strong and weak links when I talking about alternate inference chains and use those terms almost exclusively in those tutorials. I will use conjugate pair more when describing its use in certain strategies like skyscrapers and 2-String Kites. I have found that most viewers struggle more with the concept and terminology of strong and weak links and find the idea of conjugate pairs easier to comprehend. I hope that helps.

[@nayfen5767]

@@sharmilisharmili472 Both are correct, but i've never seen "conjugate pairs" anywhere, compared to strong link, which, is like, a core concept of the game. It seems to be a pretty outdated term

[@nayfen5767]

@@SmartHobbies Skyscraper and 2-string-kite are AICs techniques though, so even here, idk why we wouldn't use strong links and weak inference terms

[@sharmilisharmili472]

@@nayfen5767 Timberlake is right when he says most viewers especially newcomers don't understand links S/W , I myself didn't understand for the first time , on some other channel ofcourse, when the channel owner said that a strong link can act as a weak link and not vice versa. I used to question him , I then watched swami's tutorial abt the basics of such links which u are obsessed with.