The New Sudoku Players' Forum

[Swesent]

I have recently moved up to more difficult puzzles and, at the same time, tried to learn more advanced techniques as well. But on this one I'm currently stuck. I've tried more advanced stuff like skyscraping and kiting, but I must admit defeat at this point. This puzzle is still solvable (according to the software, so I've been getting it right thus far) but the next step eludes me completely.

I would be very grateful if someone could give me an idea on what to look for or which technique I can use to advance (the technique itself I can read up on on my own, just need to know which one). This could be an excellent opportunity for me to gather one more tool to my... ...well... ...collection of tools. Many thanks to anyone participating in my sudoku skills advancement!

[JasonLion]

Try a Unique Rectangle (type 1).

[Swesent]

Try a Unique Rectangle (type 1).

Oh man, wonderful! I was having all sorts of weird gut feelings about that 1-3 rectangle, but them two 1-4 messed me up. (And I didn't know about the Unique Rectangle (T1) at that point.) But thanks to you, my fellow forum helper, after having read up on the UR-T1, C7 quickly became a 4 and the rest fell in line like clockwork! Much appreciated - and I'll happily carry this with me to my future solvings!
Difficult things can indeed get really simple once you know the correct approach!

(And this was an Evil-rated puzzle by the way - the hardest difficulty in my sudoku application. Missed to mention it in first post.)

Cheers!

[docjohn]

Column 7 has naked triples (134) This will eliminate the 1 in r6c7

After that, you'll need an XY wing:
r8c9 is 59. This will force an 8 in r2c9 or r9c7

This eliminates the 8 in r2c7