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Chess, unlike war, is a game of perfect information

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Re: Chess, unlike war, is a game of perfect information

#61

Post by thom »

CogitoCogito wrote: post #48
thom wrote: post #38

Earlier quoted context omitted.

I suppose my problem is that the term 'perfect information' doesn't really communicate anything really interesting about chess. Whereas the equally valid term of art 'incomplete information' actually does, because it captures the fact that you lack knowledge of your opponent's strategy, but nobody ever uses that term. Chess is like navigating a maze or a minefield, it's like stumbling into an ambush. It's much more l…

> I suppose my problem is that the term 'perfect information' doesn't really communicate anything really interesting about chess. Yes it _does_ communicate something interesting. It is a basic fact about the rules of play. If there were imperfect information, it would be a different game. Poker with perfect information means everyone plays with their cards up. It is a fundamentally different game. The fact that chess…

And while I understand that you’re coming at this from a technical standpoint and I can’t argue with the definition, I still think on a human level chess is more like poker than tic-tac-toe (because you’re spending a lot of time imperfectly filling in gaps in information about what your opponent could be up to), and so the category defined by this technical term isn’t so useful in a human conversation such as we’re having, with no prizes from technical correctness. I’m not really interested in repeatedly restating the definition, I’m saying it’s not a good signifier for the differences between chess and war. Maybe that’s not interesting to you, but it is to me as a player and designer of games! And on a deeper level I suppose I’m guilty of exactly the same thing because this is a thread about poetry anyway. :P

Re: Chess, unlike war, is a game of perfect information

#63

Post by ctchocula »

pedrocr wrote: post #30
opportune wrote: post #24

Earlier quoted context omitted.

The neural networks are for the evaluation at each node, traversing the game tree is done by using the NN to evaluate how good the position is on the tree’s nodes; how it traverses the tree is minimax with a-b pruning. In my original comment I didn’t mention pruning or other heuristics like estimating the value of intermediate states because it’s more of an optimization (a very important one!) that doesn’t affect the…

AlphaZero uses Monte Carlo Tree Search not MinMax. So it does use a neural network for the search. Modern Stockfish is the one that moved to having a neural network for position evaluation while keeping MinMax with AlphaBeta and heuristics for the search.

Nitpick: MCTS is a heuristic search algorithm as well (just like minimax) that doesn't necessarily need a neural network to operate and the MCTS algorithm existed way before AlphaZero, coming from Reinforcement Learning literature. Deepmind's innovation was to replace two of the 4 classic steps of MCTS (selection step and simulation step) with neural network-based policy and evaluation network.

Re: Chess, unlike war, is a game of perfect information

#64

Post by ZephyrBlu »

Vecr wrote: post #45
AlbertCory wrote: post #39

There's one match in which it was not a game of perfect information, as Garry Kasparov says in "Deep Thinking: Where Machine Intelligence Ends and Human Creativity Begins": If you consider "perfect information" to include "knowledge of your opponent's previous games" (that's a big IF) then he did not have it against Deep Blue. IBM refused to give him any insight into what he was up against.

I don't think that's a very convincing argument, in game theory you are not supposed to be helping your opponent out, except in some very specific scenarios that usually involve zero and/or one probabilities or infinities, so they don't apply to real life. Using minimax in a non-infinite iterated game like chess, with the standard goal function, I don't think it ever happens. Winning is the optimal strategy every sin…

> All iterated games in the real world have a first game as well

They effectively don't, because the way things work in the real world is that you become known to the competitive scene long before you reach a top level tournament and people will have definitely played against you in some capacity.

If you could somehow become a top pro without interacting with the rest of the scene, then you would most definitely have a massive advantage against other top pros for a little while before they figure out your tendencies.

This is based on my experience and knowledge of real-time games like SC2 and Dota, so it may not be as applicable to Chess since the action space is considerably smaller and I don't know if knowledge of opponent tendencies is as important (I assume it is though).

I wouldn't necessarily agree all of this means it wasn't a game of perfect information, but the first match of an iterated game in the real world is almost always either inconsequential or you have access to information from a secondary source.

Re: Chess, unlike war, is a game of perfect information

#65

Post by kibwen »

dayjaby wrote: post #56
Waterluvian wrote: post #15

I find it fascinating how Chess is, in a way, stateless. Other than whether some rules like castling are still valid, you don’t need to have played the previous moves to be able to play the next moves effectively. This got me thinking: is that common in games? If I take someone’s place at a Risk board, can I play well? But in both cases, there is perhaps still some state… At least if you’re playing a human. You might…

It's not 100% stateless though: Did the king already castle? Did the pawn just pass me for an en-passant?

Which is why those balance patches were ill-advised and should be reverted for the next point release.

Re: Chess, unlike war, is a game of perfect information

#66

Post by zikduruqe »

scyzoryk_xyz wrote: post #58

My thought here is that perhaps the hidden information on a chess board is in the mind of the player. Time is also a factor - in speed chess you only uncover as much as there is time to.

And don't forget sacrifice. Not sure if AI or Stockfish or ... can emulate sacrifice for material advantage.

I learned to play chess almost 40 years ago. Just started playing last month and it is amazing at the amount of information, studies, theory and gameplay that is out there.

I jokingly understand this quote now:

"The ability to play chess is the sign of a gentleman. The ability to play chess well is the sign of a wasted life." - Paul Morphy

Re: Chess, unlike war, is a game of perfect information

#68

Post by mcphage »

esafak wrote: post #41
mcphage wrote: post #27

Earlier quoted context omitted.

> In practice, Chess is not a game of perfect information, since you generally don't know which lines your opponent has prepared beforehand What do you mean when you say "game of perfect information"? What would be an example of one?

https://en.wikipedia.org/wiki/Perfect_information

Yes, but according to that definition, Chess is a game of perfect information. So I’m wondering what definition the person I replied to is using, since their claim was that Chess is not a game of perfect information.

Re: Chess, unlike war, is a game of perfect information

#70

Post by thom »

thom wrote: post #61
CogitoCogito wrote: post #48

Earlier quoted context omitted.

> I suppose my problem is that the term 'perfect information' doesn't really communicate anything really interesting about chess. Yes it _does_ communicate something interesting. It is a basic fact about the rules of play. If there were imperfect information, it would be a different game. Poker with perfect information means everyone plays with their cards up. It is a fundamentally different game. The fact that chess…

And while I understand that you’re coming at this from a technical standpoint and I can’t argue with the definition, I still think on a human level chess is more like poker than tic-tac-toe (because you’re spending a lot of time imperfectly filling in gaps in information about what your opponent could be up to), and so the category defined by this technical term isn’t so useful in a human conversation such as we’re h…

Eh, no longer really enamoured by these thoughts, because that's really what's interesting about almost any game, but somehow I still bristle whenever people bring this up about chess.
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