Difficulty score 17. No green.

Done.

Spellacked: I only use 2 advanced techniques on experts; the alternating inference chains and Nishio. I explain alternating inference chains on my website (see my profile for the link). If you don't need to first read about the normal techniques, scroll to the bottom of my technique page and there is a link to "more advanced techniques" which explains it. There are also interactive illustrations that I hope you will find helpful.

Nishio is when you find an alternating inference chain that leads to an impossibility, such as requiring 2 different digits in the same cell.

Done.

When an alternating inference chain results in an impossibility, the Nishio technique says that the assumption that started the chain must be wrong.

My solving program only uses 1 advanced technique to solve all experts, the Nishio technique. It doesn't try to form any chains, it just guesses and if the guess leads to an unsolvable puzzle then that guess is eliminated from the possible solutions. If the guess leads to a solution, it tries a different guess. If the second guess is wrong it eliminates that guess from the possible solutions, but if the second guess also leads to a solution the solver quits and reports that the puzzle has multiple solutions.

done

go

done, ng

Drwho: although you may say "no greens" do you at least jot down what you're tracking in the inference chains/networks?

"..."no greens..."...Hubris Maximus...no way.

That puzzle was probably one of the top 5 hardest puzzles in the past 5 years....just sayin.

Wow, much easier than I anticipated.

go

done

DING. A few slow places. 16.