Is it just me or is battle-of-the-AI chess more exciting than humans?
I had realized a while ago that, as a human, the computer will give your position a score, and then you make a move, and your score can pretty much only stay the same (if you make a "perfect" move) or go down. Much of the time, it goes down.
Two humans playing each other, it's just a question: who's score goes down less each time they make a move? It became a little sad. It seemed like either you can make the right move, or you make a sub-optimal move, and the winner is simply the one who makes the fewer sub-optimal moves.
But when AlphaZero plays, and you watch Stockfish's score, the reason it wins is that it makes moves Stockfish thinks is poor, so it rates AlphaZero's moves poorly, and then all of a sudden it has an oh shit! moment when it realises that AlphaZero is actually ahead, and its score jumps. It's really a look inside the computer's head while it's being beaten by a better player.
That's more or less a description of what happens when two humans are playing over the board.
What you describe is when a perfect chess-playing computer (approx AlphaZero) observes two humans playing. What humans observe watching two humans playing (including the participating humans) is very similar to what you described AlphaZero vs Stockfish as. The only difference is we don't ask human players to ascribe a score to their opponent's move (and wouldn't expect it to be accurate)
This is also something to keep in mind to not get discouraged: Just because every move is terrible to a 3500+ chess engine at some level, it does not mean these concerns always apply to you at half that rating.
Everything else like a positional score or centipawns or even classic material points is an abstraction, that we use to summarize because we don't have unbounded or sufficient computing power to solve all possible continuations. That score apparently going down is only an artifact of our limited ability to evaluate it; the only real scores are 0/½/1 for lose/draw/win. If you make mistakes, your score will evetually drop by those quantizations; we just typically don't know exactly when, except in endgame situations pared down enough to be computationally tractable.
And it's impossible to raise your estimated score, because that estimation assumes you continue to play perfectly. There's no such concept as a better-than-perfect move to raise your expectation over what was already calculated, since that calculation already includes all your best possible moves.
* (Other gradiations between win/lose/draw are possible in such a game. Chess doesn't have such, but imagine playing Go for a dollar per point, where nuances smaller than swinging a win or draw still matter.)
A move that requires serious hardware to defend against is better than one a 10 years old laptop can hold a draw against.
For example I remember the original alphazero model that had been trained specifically against stockfish, would often take a material sacrifice for some advantage that stockfish couldn't see (e.g. sacrifice a pawn, but their bishop gets locked out of the game). I don't know if these moves were objectively good given perfect play, but they could be the only way to win now (chess is very drawish at the top computer level).
No, what I was saying is that it's absolutely possible to raise your estimated score, because your estimated score is only an estimation of who has the best position.
If AlphaZero is better than Stockfish, then by definition it will make moves that sometimes raise its estimated score, because Stockfish is only as good as its ability to estimate the score of a position better. So Stockfish must occasionally underestimate a position, and then later (after another move or two) is forced to reevaluate (because while it's worse, it's not stupid).
AlphaZero wins because, and precisely because, it believes some positions are more favorable than Stockfish does. You can almost see it as an arbitrage between the two estimations. That's what I was finding cool, and the point of my post.
Mostly I'm pointing out that these estimations represent the best guess of an ultimately limited engine. People tend to treat those engine evaluations as actual numbers, like scores in a sport like baseball or some such, but they're not.
What they are describing is that feeling you get when you suddenly realize you are losing even though you are even in pieces, because you suddenly see your opposition has superior positioning and board control
It's not a blunder, because there wasn't one particular move where the game slipped away.
At high levels, blunders are rare.
A move that worsens the position in a way that's not so immediately obvious might be called a 'mistake' or 'inaccuracy'
By these standards, it's quite possible for a game between humans to be won or lost without a blunder on either side.
Hence why I talked about the feeling you get when you realise you have mis-evaluated rather than trying to define it precisely.
From the OP:
> But when AlphaZero plays, and you watch Stockfish's score, the reason it wins is that it makes moves Stockfish thinks is poor, so it rates AlphaZero's moves poorly, and then all of a sudden it has an oh shit! moment when it realises that AlphaZero is actually ahead, and its score jumps. It's really a look inside the computer's head while it's being beaten by a better player.
Sure - you get that feeling from blunders too. But take a look at the Stockfish vs Alpha Zero games - Stockfish doesn't blunder. It it just outplayed: https://www.chess.com/news/view/updated-alphazero-crushes-st...
If you watch from here in game one you can see the "oh shit" moment, as Stockfish's evaluation drops from +1 to even to -1: https://youtu.be/Q5EPqM8gS7k?t=255
Not quite, as that would imply that each game has at most one blunder. It's quite possible for two players to blunder back and forth multiple times.
A mistake is like a blunder but you're still winning, but it could be a blunder in a worse position. An inaccuracy is a bad move that doesn't cost you.
It’s also evaluating your own position vs someone else’s - humans and computers are the same in that both will make the move they think is best, and will only have an oh shit moment when their opponent has provided a reply they didn’t expect.
The only difference is computers can see further, so while an oh shit moment for a human might be 4 moves out, with a computer it might be 20.