# Professor Penrose' puzzle

One year ago lots of people desperately tried to solve the chess puzzle of professor Penrose.

There was no problem with making a draw, but only a genius could find a win in this position. One man wrote Penrose a letter about the puzzle and the professor answered him. Here's an excerpt of his answer:

"If both players understand the position and play perfectly there is no way either player can win - black can always keep its bishops together so the white king cannot pick them off, and the 50-move rule would result in a draw. Human players understand this and don’t need to calculate the position.

However, we can see that Fritz (one of the better AI chess programs) looks ahead 20 moves and thinks black is winning. Fritz does not understand the nature of the position: It sees the material advantage and thinks it is ahead. The question is whether the human playing as white can use this lack of understanding to win. A small number of you ran the puzzle on chess programs and experimented with this.

Although we maintain that chess programs (such as Fritz and Stockfish) do not ‘understand’ the position, they played correctly and achieved a draw despite believing they had a likely win. However, some programs set to a low level of skill were so convinced they should win, they refused the draw through repeated position. They accepted losing the bishops one after another until they blundered into a losing position, allowing the white pawn on the sixth rank to be advanced and turned into a queen. To make this actually happen requires a bit of trickery and a great deal of patience.

...

Several people gave creative answers to the problem, such as to rotate the board 90 degrees and/or invert the colours. Since we were slightly ambiguous in our drawing, these solutions are legitimate creative interpretations.

We also asked you to tell us how it ‘felt’ to solve the problem. Most of you, and particularly the practised players, saw the position immediately. Others went away, came back and had an ‘aha’ moment. A few got the puzzle wrong, but this was mainly due to lack of practise or misunderstanding. We hope to study these ‘aha’ moments as part of the research at The Penrose Institute and might even contact some of you in the future to participate in this research."

To be honest, I'm pretty disappointed with his answer. It turns out that everything is relative and everyone can become a genius just playing against a weak program. But maybe the professor doesn't want to tell us the secret and still waiting for the right solution? Or the idea was to identify a genius among the people who had those "aha" moments? I'm not sure. What do you think? Fell free to share your thoughts about it all.

Reminds me of when I'm trying to get the computer's opinion on a benko or closed sicilian type of position.

Every move it changes its mind... by which I mean it will say Bd7 is the best move... and after putting that move on the board it decides it's no good. Move after move, for both players. Stupid engine.

So I try a normal looking human-like plan. No calculation. Just logic.

Of course it hates my moves, until a few moves later, then it realizes that the moves are pretty good.

The problem is when I don't know the plans, or how humans play. Then I'm stuck with the idiot computer that can't make up its mind.

it's a draw

Это шутка наверно?

DUBLYOR написал:

Это шутка наверно?

Что именно шутка?

я не все понял с переводчиком, но было видео про эту задачу где сказали, что выиграть нельзя только если поддаватся

Ну да, общий смысл в том, что выиграть действительно нельзя. Единственное "решение" здесь, как пишет профессор Пенроуз, - играть против слабой программы. Она оценивает позицию в свою пользу, и, чтобы не допустить ничьи по правилу 50-ти ходов, скидывает ближе к 50-му ходу слонов, только потом ее оценка меняется, но уже поздно. То есть выигрыш есть, только если играть в поддавки. Гениально! Профессор говорит, что ему присылали ответы с поворотом доски, сменой цветов фигур и т.д., и вот некоторых из этих креативщиков он хочет пригласить к себе для психологических исследований. Но мне все-таки до конца не верится, что он запустил в массы эту пустышку. Может, он ждет какого-то креативного и правильного решения? А может, все это действительно шутка.

why did he bother making this puzzle? he's not even a chess player. Silly if it's just hype

Stariy pirdun

Yeah, this is a difficult issue. He wanted to "study human consciousness through physics and tease out the fundamental differences between artificial and human intelligence". But still there're lots of questions and no answers.

Who’s turn is it?

Puzzle is what happens with best play. If blunders are part of the solution and no puzzle remains a puzzle anymore. You could always say, if black does not assess the position correctly he could lose. Duh!

CruiseShip написал:

Who’s turn is it?

White to move

JayeshSinhaChess написал:

Puzzle is what happens with best play. If blunders are part of the solution and no puzzle remains a puzzle anymore. You could always say, if black does not assess the position correctly he could lose. Duh!

Agreed but what's the point then? I don't think he's gone crazy even though he's an aged man.

Black to move can win with 1. ... b4xc3! (en passant).

It would be possible if it wasn't white's turn now.

Then neither side can win, obsolete chess engines can lose.

Stockfish 9+ has it's strange things too. You can reach the same position via 2 move orders but the evaluation is not the same

Polar_Bear wrote:

Black to move can win with 1. ... b4xc3! (en passant).

How do you know that 1) the white pawn made a double-step move and 2) he just made it before black's turn? I guess these are requirements for en passant to be legal

Polar_Bear написал:

Then neither side can win, obsolete chess engines can lose.

Yes! And the funniest thing's Penrose admits it. After that I'm unable to understand what it all was for and what exactly Sir Roger meant.

The point was that a human can immediately see that it is a draw. A chess engine can not. Indeed a chess engine even after lengthy analysis still sees black ahead.

The point of his puzzle is to point out that when we look at artificial intelligence computing power alone is not the answer.