What are the hardest chess puzzles you know?

Mate in 63 on Caruana vs Magnus world championship

the so-called chess 'puzzles' of today ? Or are you speaking about Chess Problem Composition ? Chess Studies ? Some of these people get after exhasting all the legal moves but one hehe' ... the one they over-looked @CheerUpChess-Youtube

@ThunderClap Just chess puzzles you find very hard to solve, I always think those that are played by chess masters like for example Judith Polgar are the best ones or chess compositions like from Morphy, or maybe puzzles that came from an incredible mating technique nobody saw coming. You can of course also post some engine generated puzzle, although they are hard to solve and understand. Just post a puzzle you find extremely difficult to solve and would struggle with yourself. Idk I feel like the task is pretty simple. You don't have to do it, but I always appreciate new puzzles.

lichess.org/analysis/8/8/5N2/8/3K1N1p/1p3knR/1Pp2prb/n1B2b1B_w_-_-_0_1?color=white
Mate in 14. Sorry for deviating from your rule.
I only posted this puzzle, because I think that a human will find the solution faster than most engines.

@Bishop1964

I solved your first chess puzzle. It took me only seconds to find the right first two moves, but two hours to think every single variation through that goes up to 15-20 moves deep. Here is the evidence (I decided to record my thoughts):

www.youtube.com/watch?v=czL7SY2u1ZE

@sgtlaugh I solved your puzzle aswell, it took me about 30 minutes to get the solution (of course first try, otherwise I would consider it unsolved and failed) - it was challenging, but personally I thought it was still a lot easier to solve than Bishop's one. I made a video as evidence aswell, you can watch my thought process if you like on how I could savely solve it. Thank you for posting the puzzle, it was very interesting and a very untypical idea indeed, all about tempo initiative.

www.youtube.com/watch?v=YM-TfhKBBaU

@CheerUpChess-Youtube said in #26:
> @sgtlaugh I solved your puzzle aswell, it took me about 30 minutes to get the solution (of course first try, otherwise I would consider it unsolved and failed) - it was challenging, but personally I thought it was still a lot easier to solve than Bishop's one. I made a video as evidence aswell, you can watch my thought process if you like on how I could savely solve it. Thank you for posting the puzzle, it was very interesting and a very untypical idea indeed, all about tempo initiative.

@CheerUpChess-Youtube congrats. It was a tricky one for me. I didn't spend so much time though. It's not the hardest puzzle I've encountered, but I was unable to find some of the harder ones. Perhaps I can share again if I find them if you're up for it.

Nice video btw. Didn't see the full video as it's too long, but I will be back again later and check out your other videos. Will also subscribe. Keep up the good work and best wishes mate!

@Bishop1964 I solved the second chess puzzle you posted. Now I got all three that I wanted. It was not even mate in 16, but mate in 19 moves - I still found it interesting, but I needed to adapt my solving technique. In this video you can actually see how I solve the puzzle move by move, not visualizing it from the starting position, because that would have taken ages. I still considered it solved, because my calculation was correct.

www.youtube.com/watch?v=svtsZHOkgd4

Guys I finally finished my blog with 10 hours of work.

Thank you so much @sgtlaugh and @Bishop1964 for providing those beautiful puzzles. Also thank you @corvusmellori , @Mr_Kuryakin , @TalesAmaral and @dr-bongstein for your suggestions.

Here is the finished blog:

lichess.org/@/CheerUpChess-Youtube/blog/can-you-solve-all-chess-puzzles/WuYREJ7K