Studies to Troll your engines with

2 important points with that puzzle, the white pawn ha ls to move to the opposite colored square as the one the queen is currently on, and take the c5 pawn first. Taking the c5 pawn first will allow black a waiting move of c5-c4, switching the tempo so the b3 rook is defended from being captured with checkmate. Same with advancing to h4. It has to be timed perfectly.

You're right, mine did too, on Android phone.

I have an update on this position:

Stockfish could not see the forced mate in 67, but after I played the moves out in analysis mode, it saw it once I backed up move by move back to the starting position, saying M-67. I wonder if there is any learning influence in the engine algorithm that would remember this next time I set up this position?

Edit: nope, it doesn't remember the analysis lol

Actually it usually does as long as you don't restart the engine or clear the hash table, there's even a term for it: it's called "forwards-backwards analysis".

As I recall Stockfish never solved that one on my computer, but the special modified version of Stockfish named "Crystal 5 KWK" did. Crystal is designed specifically for mates and studies and difficult tactics and it is capable of playing a full game of chess, but because of the modifications it plays about 100 elo weaker than Stockfish in a full game from start to finish.

If you want Crystal you can download it from this page: https://ipmanchess.yolasite.com/compiles.php

Make sure you choose the right compile for your cpu after you unzip it because there are 6 compiles for it (and that's why it's 126MB)

Here is Crystal on the mate in 67:

Stockfish 15 I think. I ran it on an iPad, so I’m not entirely sure.

Is crystal available in android devices?

I think that it is, but it didn't come as an .apk file so I didn't know how to install it.

Try here: https://chessengines.blogspot.com/2022/12/chess-engine-for-android-crystal-5-kwk.html

Position #13

The engine troll factor on this one is definitely 10/10, engines are completely and utterly helpless in this position, and I know of absolutely no engines that solve this one yet.

White to play and win:

You're not going to believe this, but the latest development version of Stockfish dated 04/22/2023 solved this even faster than Crystal did, I'll post a screenshot so you can see:

I've tried to get stockfish for windows several times it didn't work. Which version is that? Is it a full paid version or something?

It's completely free, they release several development version in between the "official" versions. Here is the link to the development version, make sure you download the correct compile for your cpu, mine takes the "BMI2" compile which is "Windows x64 for Haswell", yours might be different if you don't have a "Haswell" processor. If you aren't sure what compile to get then grab the safest compile that is compatable with all CPUs which would just be "Windows x64"

here is the link: https://abrok.eu/stockfish/

And here is a screenshot of the site:

Position #14

The troll factor on this one is about 9.8 meaning that maybe a mate finder can find the solution, or an engine that has been modified to find mates (but can still play a full legal game of chess). I'm posting this as a study meaning that all your engine must do is find a win, but I should mention that it works out to be a mate in 20 if you want to try and find it.

White to play and win:

If you look at the position carefully all you must do is get a Knight to the f4 or h4 square to deliver the mate, but how? Good luck engines, you'll need it .

Position #15

The engine troll factor on this one is probably 10/10 as I have found no engine that can solve it, and actually the IDEA is not too difficult to grasp if you look at it carefully, but engines are absolutely clueless on this one.

White to play and WIN:

That confused me, it is very difficult.

The Rooks can stop the Queen from checking white's King and since they threaten mate at the same time the Queen must be sacrificed to stop the mate threat.

I don't think I'd ever play all those moves correctly.

I probably wouldn't either, but what I meant was the IDEA was simple, and certainly something you would think an engine could find and make the correct first 2 moves from the root position.

As you say. the black queen is a spectator. But White's queen's side pieces other than the king have to remain rooted to maintain that. Your only comment on the final position (shown) is "1-0", but how does White go about winning from there?

Here you go all roads lead to mate: