The New Sudoku Players' Forum

[jeffcia]

Screenshot_2015-04-14-09-23-43.png (243.73 KiB) Viewed 744 times

What can I do from here other than guess and check (50:50 shot).

Thanks!!

[ArkieTech]

Look at 1's for a skyscraper (r57) to remove the 1 candidate from r4c8 and r8c9 and solve the puzzle.

[eleven]

There are several options.

If you are familiar with "remote pairs", there is one in cells r8c1, r6c1, r5c82, r5c9.
One of r8c1 and r5c9 must be 1, the other 4. So r8c9 cannot be 1 or 4 (must be 9).

Or (as Dan mentioned above) there is a skyscraper for 1 with strong links in rows 5 and 7 and the common column 2: if r5c9<>1, then r5c2=1, r7c2<>1 and r7c8=1. So one of r5c9 or r7c8 must be 1, and r4c8 and r8c9 cannot be 1.

Another way is, that in column 8 not both r4c8 and r7c8 can be 1, so either r4c8=4 or r7c8=9 -> r7c2=1 -> r5c2=4. So one of r4c8 and r5c2 must be 4 and you can remove 4 from r5c9.

[jeffcia]

Thanks for providing strategies rather than just solutions!

Do you guys have a good site for me to learn about skyscrapers and remote pairs?

You guys rock - thanks!!

[DonM]

Another: To prevent the deadly pattern of 14 in r23c3 and r23c5, 6 must occupy r2c3 or r3c3 so you can eliminate the 6 in r1c3.

[SteveG48]

Thanks for providing strategies rather than just solutions!

Do you guys have a good site for me to learn about skyscrapers and remote pairs?

You guys rock - thanks!!

Google "Hodoku". It's actually a free program for creating and working Sudoku puzzles, but it also has a great on-line tutorial of solution techniques, including skyscrapers and remote pairs.

[jeffcia]

Thanks, Steve - I will install and take a look.