How To Solve Using Remote Pairs And XY Chains - Sudoku Handmade Classics #47

In How To Solve Using Remote Pairs And XY-Chains - Sudoku Handmade Classics #47 by Smart Hobbies, I solve “Foraj Paroj” by Bondye. “Foraj Paroj” means “far couple” or “remote pair” in Esperanto. I use Remote Pairs along with XY-Chains to crack this puzzle. I solve the entire puzzle logically and explain each strategy to you the viewer as I apply them. Thank you Bondye for permission to feature your puzzles on my channel.

The puzzle can be found at the following link:

This video is part of my Sudoku Handmade Classic series on my YouTube channel, Smart Hobbies. The goal of this series is to share the joy of solving Sudoku puzzles with you.

Strategies demonstrated in this video:

Hidden Single
Naked Single
Pointing Pair
Claiming Pair
Naked Pair
Naked Triple
Remote Pair
Empty Rectangle
Unique Rectangle Type 7
XY-Chain

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Let me know what you think and how you did in the comments below. Thank you so much for watching.

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[orettepalmer]

thanks for the puzzle solve that nailed down one of the trouble some techniques at least to me. I think I finally got it.

[v.r.mallikapalanisamy]

Great sharing nice veideo superb 👌 stay connected friend and nice day 🙏💐🤗😆

[Ramakrishnagm]

Solved 12 min. Because of I saw vedio 22 10 23 intermediate pairs, but I didn't see this vedio. Nice puzzle. Thanks.

[paulakeay]

Loved that puzzle and the remote pairs, I think this is a good showcase for that technique. I slogged my way through at 26.00, but I wasted at least 10 minutes working permutations of XY chains, when actually I just needed to rescan and ultimately I used colouring and disambiguated them in box 1. I missed your empty rectangle- a technique I completely understand yet fail to spot by myself when solving!

[laszloliptak]

Nice puzzle and solve. I solved it in 17:55.






In f-puzzles and other solvers it really helps that you can color the 49 pairs, and then it is MUCH easier to see which cells see two 49's of different color. I am happy that using uniqueness at 10:15 did not really help in the solve :) At 13:32 there is a shorter xy-chain, a broken 457 triple in cells r1c5-r3c4-r9c4, which eliminates 4 from r9c5. After this, at 15:12, the coloring of 49's makes it really easy to see that there can't be a 4 in r9c4 because of the chain

[AnonimityAssured]

What a lovely puzzle: no 4s and only one 9, with 30 givens and rotational symmetry. It's almost a disappointment to discover that it can easily be done without notation (74 = row 7 column 4):
74, 52, 58, 87, 96,
55, 95, 15, 76, 62,
48, 63, 47, 99, 79,
78, 39, 88, 23 (remote pairs),
41 (colours on 4s), and the rest is automatic.
I found various other ways forward, but one way is all we need.

[JohnRandomness]

I managed to solve the puzzle with remote pairs but a minimum of chaining. With ten digits placed and the bottom six rows centermarked out, I noticed eight 49 cells. Coloring them seemed a good idea -- blue and yellow, with green for cells that could be either. I placed more digits and got more 49 cells, and filled in the rest of the grid. I colored all possible 4 or 9 cells with blue, yellow, and (only in column 5) green.

I found a short easy-to-follow chain. (XY-chain?) If a particular blue (49) cell were 4, it would create an 89 pair, creating a 46 pair that pointed toward a blue 47 cell. (The cell was 4 or 7. If 4, then the cell was blue.) Consequently, that cell couldn't be blue-4, couldn't be yellow, couldn't be 9 -- it had to be 7. That cracked the puzzle.

4:40 In other words, cells that see both (mandatory, 49) blue and yellow cells couldn't be either 4 or 9. My first elimination placed a 6 in R7C1.
6:00 Your cursor was on one of the 49 cells that placed the 6. In addition, it gave another 49 cell. Coloring would have made it visible.
9:30 I'm now shouting mentally at the screen about R7C1 and 49 elimination.
12:10 Just after you said, "57 47", I noticed the 45 in block 2. It gives you a Y-wing attacking the bottom of column 5, placing a 6 there.
15:00 After placing the 6s, a lone 2 is in block 1. It took me a while to see it in my solve.
15:50 With coloring, you don't have to count 49 cells every time.
17:00 You can use remote 49 pair to attack the 47 cell at the bottom of column 4. (That's the blue 47 cell I attacked with my short chain.)

Thanks for the video. I see in the comments various different paths through the puzzle. I used colors for the remote pairs, but the colors went beyond remote pairing.

[thomaswilke]

Foraj Poraj means “Remote Pairs” in Esperanto. Esperanto is an artificial language created for use by people in European countries who speak different languages. I don’t think this language is widely used anymore since English is now the de facto universal language

[stegra]

A simpler route at 13:30 is to notice that...




5 in r1c5 puts a second 5 in box 2 via r5c5, r9c5 and r9c4.

I managed to do this notation free but watching the video I wonder if I got lucky. I eliminated the same 5 but it was because it put a 49 pair in r1c4 and r3c4 breaking r4c4. However, I can no longer see how that was the case.

[jrbr]

I don't see how 6 is solved at 14:14. There are more 6s in column 2 and row three.