The last puzzle has an amazing story IIRC. A composer set it up at either the world championship or just some tournament, and the best players in the world at the time (Botvinik, Kasparov etc.) couldn't solve it. Then the magician from Riga took a look at the board and after some time couldn't solve it. So he went for a walk to ponder the position, When he came back he produced this solution. No wonder engines can't solve it, the best players in the world needed a magician! Edit: Upon rewatching the video I sourced this knowledge from (It's an Agadmator video titled "Grandmasters and Engines couldn't solve it, then came the Magician from Riga") I realized Botvinik was _not_ present at the tournament, however it was still a strong tournament with players like Kasparov, Karpov, Larson and obviously Mikhail Tal. Check out Agadmator's video as it goes through the puzzle in much greater detail as he dedicated an entire video to it :)

Tips get the strongest possible analysis, use: - Chess Engine: Stockfish 16 (45MB download) The "lite" version doesn't have NNUE, so it is basically Stockfish 11. - Number of Lines: 1 The more lines you have, the more resources Stockfish has to spend computing the 2nd, 3rd, 4th... best moves, instead of focusing on trying to find just the best one.

The second one is probably the most beautiful puzzle i have ever seen

The 3rd puzzle is ridiculous. There may be 0.001% chance that Stockfish missed the initial Queen sac, but there is 0 chance that it will miss the mate after 6:46! That position is so simple even I, a merely 1200 elo player, can figure it out.

Crazy how in the 4th puzzle the knight can’t return to A5 after an odd number of moves

Lichess engine found them immediately.

10:33 It is a forced mating line, but mate in 32 moves or less instead of 15 moves.

Stockfish dev finds the first and third positions near instantly. And the second after a couple minutes. Leela is also very fast on the 5th one. And some more puzzle focused engines like crystal can get all of them. Also you should get off of the lite version. That uses the old HCE (handcrafted eval) that hasn't been updated since before SF12. So it will have less positional understanding than NNUE.

And that's why bishops are better than knights

"Humans love to sacrifice queens " 😂🤣😂🤣😂

The latest Stockfish dev version solves #1-#4 instantly and requires a depth of 49 ply for #5, which could be 10 minutes or more on slower hardware. Stockfish Crystal solves all puzzles instantly (e.g. depth 20 for #5).

Stockfish essentially only doesn't find these because only one line is enabled. Enable more lines, and stockfish again can find the solutions.

All positions analyzed with Stockfish 15.1 to satisfy my own curiosity about whether an engine could solve the puzzles on a better computer. 1. Mate in 8 found at depth 31, starting with Qh5+. 2. Engine still thought this was a draw at depth 72 and over 12 billion nodes searched, regardless of variations. Once Bc3 is played, it found the right continuation immediately before I could record the depth. FAIL 3. Qf6+ found at depth 27, but only by asking for 2+ variations. Not found by depth 60 with one variation. However, it found a defense you didn't mention in the video which is sacrificing the black queen back with Qxf6, exf6, Kxf6 where black barely survives at a +5 evaluation. It immediately notices the mate in 8 after Qf6+, as sacrificing back the queen is the only defense given. 4. Mate in 16 found at depth 126 starting with Kxe1. Not found before depth 126, but it only took about 10 seconds to get there. Much sooner than expected, as mentioned in the video. 5. Forcing line found at depth 25 starting with a +3.7 evaluation, creeping up to +10.13 evaluation by depth 42 and 15 billion nodes. TL;DR most of these puzzles just need a stronger computer or multiple variations to solve. #2 is the only one that could not be solved by the computer without being given the first move.

Every one of these "the engine can't find this" I have ever seen has been wrong, and Stockfish found it in a second or less.

Stock fish 16 on lichess sees it, suggesting mate in 12

Latest version of Stockfish WAS able to find the solution to the last one with about 10 minutes of searching. The second longest puzzle was the second one, which it found in a minute or two. All the others were instantaneous.

(ryzen 7950x, stockfish 28 threads 130gb 4400 ram 2 lines) estimates btw #1 35 to 38 depth 10 -20 secs #2 65-68 depth 60-90 secs #3 unknown 5+ mins over 53 depth stockfish struggles to find mate but find Qf6+ instantly #4 instant 100 depth? #5 unknown 44+ depth 4+ mins but Nf6+ found instantly

the fact that the chess engine can't even find every possible move pretty much shows that there might still be the most beautiful lines out there that have never been discovered in history, akin to whole continents that are yet to be explored

Now we know that another variant of Mobius is just a chess presenter

Spenny Thompson is the best!

And that’s why HCE engines are outdated

2nd one is insanely amazing

00:19 yeah bro thats stockfish 16 lite... like 200 elo lower than regular

1st puzzle : lichess board analysis found mate in 8 with white 2nd puzzle : same but mate in 12 3rd puzzle : if you limit depth it says +1 or +2, but if you increase it, engine finds a draw if both player play perfectly. ( not a forced mate as you said ) 4th puzzle : engine find mate in 16. 5th puzzle : as you said, not a forced mate. +7.2 so it must be mate in 30 or more. Chess are just way better than us. If there is a problem we can solve and an engine can't, it has to be more than 20 moves, with a lot a playables moves each time, but easy enough for a human. good luck.

Leela BT4 solves these puzzles instantly.

Wow, I rarely like videos on KZfaq but this one deserves a big fat like Very nice, concise video and great presentation as well

Damn I'm going to show these to my friends at the bar and at the library

I love this Just made my day

Maybe someone said this but puzzle 3 isn't a forced mate at the starting position. At 6:40 - 2... Qxf6 leave white slightly ahead, but definitely not mating (following 3. Bh6+ Kg8 4. exf6. And stockfish picks Qxf6 over Kh8 or Kg8 because both are mate in 8. Hardly a "checkmate engines can't find" when it's not a forced mate at all. The last puzzle is really cool because you can see how happy stockfish 16 is even for a second after 3. Bc3. You can see it briefly scan the position after black's second move, and dismiss it. And after the move, the evaluation for black is like +7 for a few cycles before dropping to -3.5. It's also interesting because leela more accurately discovers Nf7+ form the outset, whereas stockfish wants white to play something like Nxe3.

So all those blunders which I had in game analysis were briliant sacrifices with winning idea far away for engine to see.

Nicely done

Chessmaster 10th edition (2004) found the first checkmate in 11 min. and 2 giga nodes.

I've heard that the reason chess engines struggle to find certain check mates is because the calculate one move at a time, places a value on each move and continues down the path of different move orders until they find which path has less risk and more value. When one move initially is very bad in terms of value, like sacrificing your queen, the engine will persue other paths first until they eventually calculates the queen sacrifice. So they will eventually find it, but humans will sometimes find a queen sacrifice faster because of our own interest in calculating a queen sac before other lines.

The last puzzle 🧩 was my favorite.

Stockfish: I can't solve this with all my intelligence. Some former monkey: But what if you play stupid instead? Stockfish: Ah yes, now I see it.

Wow they were all nice, but that last one may be the nicest thing I've ever seen on a chessboard. Great video, more of these plz

Just increasing depth allows to find the answer instantly...

Either LC0 or SF16 find solution in seconds in EVERY puzzle here

The last puzzle was also analyzed by levi😂

those are some beautiful checkmates

I recall the 2nd puzzle is something Danya once showed

King moves... discovered checkmate😅

I am aware that it is sometimes difficult to introduce chess to people who think it has in some ways being solved. But I don't think the solution is being missleading about engines. Stockfish properly setup has no problem with any of these.

This is the most incredible thing I've seen in chess lately.

2 positions that Stockfish 16 can't find on a cheap laptop in a reasonable amount of time, one that takes over 3 minutes, one that takes 12 seconds, and one that takes milliseconds: 1) rnbq3r/pppp4/3b1pkp/5p2/2BP4/4P3/PPP2PPP/RN1QK2R w KQ - Mate in 8 (12 seconds) 2) n1QBq1k1/5p1p/5KP1/p7/8/8/8/8 w - - Still draw after 9 minutes @depth 74! 3) r2q1r2/1b2bpkp/n3p1p1/2ppP1P1/p6R/1PN1BQR1/NPP2P1P/4K3 w - - +3.84 after 42 seconds 4) 8/8/8/2p5/1pp5/brpp4/qpprp2P/1nkbK3 b - - Checkmate in 0.00 seconds! 5) 8/3P3k/n2K3p/2p3n1/1b4N1/2p1p1P1/8/3B4 w - - It takes 3:10 minutes @depth 43

This was cool, thank you!

The first one is not seen by the computer because it is not mate in 8, it is only mate in eight if the black king takes the queen.

3:47 Zugzwang with a bQ and a wB. Beautiful! (Zugzwangs with line-pieces which are not trapped are rare.)

this is an interesting case of p vs np completeness

The whole idea that humans can still play SOME chess better than computers is amazing. They should have used this idea in one of the Terminator movies (or Matrix movies) as the mechanism to get humanity to beat the robot overlords.

1) real stockfish solves in 10 seconds 2) real stockfish can't solve, looks like a bug, not a "horizon effect", stockfish does not evaluate this move even on depth 100. But with Syzygy endgame tablebases, it should be able. 3) real stockfish finds in 40s. 6:33 Kg8 is a human mistake, causing M+8. Instead, Qxf6 and game continues (not great for black, but not mate) 4) real stockfish solves in 1 second, even though stockfish is not designed to solve illegal positions 5) real stockfish can't solve Note that "in-browser stockfish lite" is like a "book of good chess ideas", not a full-blown engine. Web-browsers are limited in terms of calculations (not enough memory, limited threading, limited instruction set running in vm).

Great video thanks

For me in first puzzle, both Torch and SF16 get mate instant. Second was both broken. Third Torch get Qf6+ move, SF16 nope, but Torch moved Qxf6 not Kg8 that prevent mate. Fourth - Torch didn't get mate, SF16 get mate in 16 in an instant. Fifth - Torch didn't get your move Nf6+, SF16 get it but didn't go for fork Nf7+. I was using full version of SF16 not lite.

3:25 why not Qf2??

The explanation for why engines don't see the second position is quite naive. I think the real reason has to do with a heuristic called "null-move pruning", which is known to make it harder to find tactics that involve Zugswang. In this case it involves it many times in a row, and the heuristic makes the engine basically never see it. It turns out the null-move heuristic makes programs much stronger in general, so that's why most engines based on alpha-beta search use it.

That was fun! Thx

So he says if you force the engine to analize a certain line, it will find the winning sequence, but just before he played the rook sacrifice the engine already considered it the best move, which means it has to have looked at that line in more depth. And after he played it, the engine still thought it was better for black. There were no more obscure sacrifices after that, so that's the only one that got me like, hmm... a bit sus.

last one solved by only Tal

The second puzzle is a perfect example of engines not understanding a concept. This is because computers don't understand anything, they jjust ... compute.

I have some ones i invented that the engines also cant solve

TBH you are using stockish lite (in browser) which is about 40% of the capability of the full stock fish and slower for it to work in browsers. I tried all these puzzles in full stockfish and komodo (both using GPU acceleration), both of them solved them seconds. Only leela couldnt solve all of them, but since leela is an AI you have to teach it first and then it will solve it.

No "Horizon Effect" - the engine doesn't find the second "solution" because is not a forced solution. What if you keep attacking the bishop with the queen? Nice study idea, but It's just a draw.

So the computer doesn't consider the first move if seems stupid?

How can an engine not calculate a forced mate in 8? Makes no sense

In that first position, what if the black hing moves to g7 (and then f8)? Seems like there is no quick mate.

second puzzle: what if white move their bishop to B6?

way too dank chess puzzles

Have you tried cloud stockfish?

first pazzle: What if instead of "bishop B5 check" black will play "bishop take h2"?

isnt that third example a leela game from cccc?

Nice puzzles, but please stop hiding the board with analysis windows, or by removing it from the screen.

what did u mean the third problem doesnt lead to a forced mate?

Why can't the computer find a mate under 18 moves when you have set the settings to 18 lines deep?

atoms in observable universe are much more than legal and possible to reach positions in chess for example a king cant castle after moving already and ao on

Awesome video. Could’ve done without the last one considering it’s cooked.

Nice puzzles! That said, my quite old version of Leela Chess Zero running on a 2020 laptop was able to solve #1 and 3 in under 15 seconds, and #5 in about 2 minutes. Stockfish is not the best engine around imo.

In the second puzzle, can't Black just play Qf8 after we play Ba1?🤔☝🏻

4:13 doesnt Qf2+ just win the bishop? ahhh but it's a queen promotion mate that follows regardless of where the king moves. ahhh i see

I don’t get how the Horizon Effect works in those particular cases. For instance, if we take the 2nd example, white have « only » 18 possible moves. How come the engine cannot calculate the continuation for these only 18 possible moves ?

Pour le 2e mat, j'ai mis la position dans Lichess avec le réglage par défaut, il a trouvé mat en 12 en moins d'une seconde

6:35 what if the queen takes the pawn instead of king moves? White is better but there's no forced mate anymore (or at least I can't find one)

I think Tal was the only person to solve that last puzzle in a group of grandmasters. Or so the story goes. Either that or it's very similar

2:47 black can just move the pawnand get the king to escape (2nd puzzle)

0:54 and he sacrificed... THE QUEEEEEEN

Um, well, technically, since there are only a finite number of positions, if you dont limit depth and don't alpha prune you can find all of these

I Solved the THIRD puzzle and I am super proud of it!!!

On the 2nd puzzle why cant queen just keep checking king

5:05 》Claude Shannon has entered the chat.

Excellent

Okay, here me out, what if we gave and two engines, time to scour every single possible move and make it think of the position of every move, what would the possibly "perfect" game of chess be, as stockfish although the #1 bot, is limited to a point before perfection, what would the true best game of chess be

3:15 "Why not a1? You'll see in a second." I'm afraid I don't see it. 😞

3rd one is actually not the forced mate - so as long as after like 2 minutes Lichess shows +4, it's correct. Black queen can sacrifice for the pawn!

I wonder - is there a position in which the engline would think that black have a mate in X but in reality it's the white whcih can force a mate?

What about Qf2+ 3:20

11:55 g4#

12:34 still g4# but this man didnt find it.

How is Leela handling these puzzles? Does anybody know ?

At 326 queen f2 wins for black

In 3:17 ther queen f2 forking the king and the bishop which loses a bishop and white would lose after the queen takes the advanced pawn then the a file pa2n is unstoppable and black wins

1:08 actually that’s king h4, not h8…..