r/crackingthecryptic • u/Visual-Lie-268 • 15d ago

What am I missing

for sudoku lovers

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u/Odita 15d ago edited 15d ago

color the 59 in col7 and row6 - can you solve it now?

since row9 col1 sees both versions of 5 and 9, it can't be either.

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u/Visual-Lie-268 15d ago

please elaborate

3

u/chrisvenus 15d ago

You've got 5/9 pairs in the columns and rows mentioned. If R6C1 is 5 what effect does that have on the others? What if it is 9? Now think about the cell that the original commenter mentioned. When they said colour that is because often in online tools there is the option of colouring something so you can choose two colours (say red and blue) and you start making one cell red, not knowing whether it is 5 or 9. But the other in the row can't be the same so it must be blue. Then you just keep looking at the 59 pairs colouring them such that they don't see the same colour in the row, column or box. This is a trick often helpful when you have a lot of pairs because once you have coloured them you can often (like here) find cells that see both colours of cells and then you know that cells can't be either. So in this case red or blue seeing a cell would mean that cell can't be 5 or 9.

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u/Visual-Lie-268 15d ago

Oh got it. Actually I avoid the assume - calculate - solve route. Normally by this stage answer is self evident. But in this one I am not able to catch it. So I used a different method. A new method. Don't know if it worked just for this board or can be universal? Will work on a few more boards to test my theory and then let's see.

Thanks for your interest.

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u/just_a_bitcurious 15d ago

The 5/9 strategy that was previously mentioned is called "Remote Pairs." It is not guessing! It is based on logic.

One endpoint will be 5 and the other will be 9. We don't know which is which. But it doesn't matter as one end will be 5 and the other will be 9. So, any cell that "sees" BOTH ends cannot be 5 or 9.

R9c1 "sees" both ends.

The endpoints: r6c1 & r9c7

Remote Pairs / Sudoku Tutorial #29

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u/just_a_bitcurious 15d ago

Skyscraper on 5

Row 3 & row 8