Empty Rectangle and the LOGIC Behind It 

Great lucid explanation... Thanks a ton from Kuwait 🙏

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.

Thank you for taking the time to explain every step of the process so clearly!!! 😀💟

This helped me finish the NYT hard puzzle today!

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.

Thank you so much for this long explanation, finally I got it! Greetings from Germany!

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.

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.

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

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

Is it necessary that the conjugate pair should be in different blocks,Or they can be in same 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 ?

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....

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.

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.

Jesus you went on a bit

She stops explaining what is meant by "one row and one column" at 5:10.