Empty Rectangle and the LOGIC Behind It
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- Опубликовано: 28 авг 2023
- Lesson #17: The Empty Rectangle appears more often than you would think, you just have to know how to look for it. In this video I explain the pattern first, and then show you two real Sudoku puzzles in progress to demonstrate this very useful pattern. I hope you enjoy this tutorial, and, I hope you Learn Something!
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Great lucid explanation... Thanks a ton from Kuwait 🙏
Thank you for taking the time to explain every step of the process so clearly!!! 😀💟
I was so stuck...all that was left in the puzzle were pairs, triplets, quads, quints, septs in every direction and within all blocks...nothing to eliminate! Also no x-wings, x-y wings, xyz wings, w-wings, and no skyscrapers that could eliminate any little number. Then I happened upon this video. Thank you so much for the perfect explanation....one empty rectangle solved the puzzle completely. I have to start always looking for empty rectangles in every puzzle I do so that I will always have it in my arsenal of techniques.
This helped me finish the NYT hard puzzle today!
Thank you so much for this long explanation, finally I got it! Greetings from Germany!
Problem is to remember to look for it the next time we're stuck! 😊😊
I Like your nuts and bolts approach in describing these patterns.
You should write a book or make one available for download. It would be well worth the purchase.
Very clear and concise explanation. Thank you very much
Well described, thanks.
Very clear, thanks
Amazing! thx from germany!
Smart girl, thanks for your lesson and your time.
You're the best.
Thanks
Thanks for this! I didn't use it specifically, but it didn't help. Using a conjugate pair like that makes a big difference.
In your last example, isn't there also an empty rectangle related to the 2's in block 9 that would lead to the elimination of 2 in the lower left corner of block 3 (cell 7)? This would then leave 2's in cells 3 and 9 of block 3, resulting in the same final result of eliminating the 2 in cell 6 of block 9? Would one of you smart folks let me know if I'm understanding the process? Thx
Really aweome technique. Just used this with multiple numbers to solve a puzzle I had completed all pairs, triplets, then x wing, y wing, swordfish and slanted skyscrapper were all nil, but I had several key empty rectangles that helped me solve the puzzle. This technique is really easy to spot, understand and apply.
I'm having a hard time figuring out which number is considered to be in the same row/column. As an example, why couldnt the 2 on h9 be considered the one on the same column then removing the 2 from C6 instead? For the example on 12:53
If you start by choosing the 2 on H9, you’d need there to be only one other 2 in row 9. This is what she means by “conjugate pair”- there’s only two instances of a given digit (2 in this case) in a particular row or column. However, because there are more than two 2s in row H, you can’t use the 2 on H9 as the basis for the empty rectangle trick.
You can use the 2 in column 6 because there are only two 2s in that column, meaning it is part of a conjugate pair.
Hope that helps!
I'm really enjoying your Sudoku videos; thank you for them.
Question: who determines--and/or HOW do they determine--whether a puzzle is hard or "easy". I'm assuming that the number of slots out of 81 slots which are blank is one factor. But what else: is it part of the algorithm that generates these puzzles? Is there Sudoku "checker" that rates them (like a restaurant reviewer...) . Always wondered....
Is it necessary that the conjugate pair should be in different blocks,Or they can be in same block?
Go to 6:40
A pair (same numbers!) in ONE block?????
In your last real world example, does the logic of eliminating the 2 in the 9th column also imply that the 2 in the same row immediately adjacent in column 7 also get eliminated ?
No, because it doesn't see the empty rectangle. Only the one seeing the empty rectangle can be eliminated.
If you have a valid puzzle, you can switch rows with columns and produce another valid puzzle.
If you have a valid puzzle you can switch 2 rows in the same block and produce another valid puzzle.
Once you know these 2 concepts, you do not need to belabor all the different patterns for a solving technique.
Jesus you went on a bit
I think that your explanation for calling this method an empty rectangle is wrong.
The empty rectangle refers to the area that consists of the block , the conjugate pair, and the cell that has the number that would be eliminated. When you connect all these they create a rectangle shape.
She stops explaining what is meant by "one row and one column" at 5:10.