Students at Berlin University Build Chess Game on Ethereum

https://news.bitcoin.com/berlin-students-chess-ethereum/

by posternut • 10 years ago

78 38 10 years ago

news.bitcoin.com

meinhard• 10 years ago

chess. but with blockchain!

snippet22• 10 years ago

Oh the language built for lawyers...yay

Aenima• 10 years ago

Ethereum chess had significant latency and the impossibility of consensus... sounds like lawyer's work to me.

DennisP2• 10 years ago

It's not a "language built for lawyers." It's a simple imperative language with curly brace syntax and strong static typing.

daveguy• 10 years ago

I wonder if we can squeeze coins out of it.

matthewcford• 10 years ago

half the chess pieces go missing

seltzered_• 10 years ago

direct link to students medium post: https://medium.com/@graycoding/lessons-learned-from-making-a...

link to their github repo for ethereum chess: https://github.com/ise-ethereum/on-chain-chess

SamBam• 10 years ago

I don't understand why verifying the checkmate end state is any harder than playing each turn.

They say

For checkmate and stalemate, to verify the condition all possible moves have to be calculated and verified, which is unfeasible on the blockchain.

But "all possible moves" is only one-move deep. We're generally talking a couple dozen possible moves at most. If the system can't calculate a couple dozen possible moves, how is all the basic move logic being done "on chain," as they say?

gjem97• 10 years ago

I have to admit ignorance about this implementation, but as I understand it evaluating a single move is computationally much simpler. That is given a piece, validate that the proposed move (decided on by a human) conforms to the rules of chess, and is valid for the given board state. Verifying a checkmate (even if only verifying checkmates proposed by a human player), means going through every one of the opponents pieces to see if it can be used to improve to a non-check state.

tromp• 10 years ago

Verifying checkmate is essentially doing a 2-ply search: for all moves i can make, the opponent has a reply that captures my king. This is more work than verifying normal moves, where a 1-ply search suffices to check that kings are not left in check.

They could have simply adopted blitz chess rules, where the goal is to capture the opponent king, and leaving your king in check is not illegal, to avoid all this extra computation...

DennisP2• 10 years ago

Alternate solution: (1) Player A announces "checkmate." (2) Player B either agrees (ending game), or moves a piece. (3) If Player B moved, then player A can end the game by capturing the king.

This could allow for player error, but to prevent that you simply have client-side code perform the steps.

crispyambulance• 10 years ago

Perhaps they meant that only certain "stalemates" are computationally infeasible with their ethereum platform? There are stalemates where it is impossible to checkmate the King, but where the players can just keep making moves indefinitely.

mikeash6• 10 years ago

Those aren't stalemates, technically speaking. Such a game would end either when the players both realized it's pointless and agreed to a draw, or when it's gone on long enough for the same position to repeat three times, and one player claims a draw. The second case may well be computationally infeasible too, since it would involve keeping and searching the entire history of the game.

drdeca• 10 years ago

Well, it also has to check whether they would be in check after each of the possible moves, and this involves checking (all?) of the opponent prices.

onion2k• 10 years ago

There isn't really any need to check the board state is in checkmate anyway. It's a nice feature, but admitting checkmate is essentially the same as resigning, so just let the player carry on and give them an "I resign" button. They can't make a move, they have no choice but to click it. If they don't click it within a given timeframe that's the same as if they just walked away mid-game.

You'd probably need a second button that instigates the stalemate procedure if both players have pressed it because that's a much more complex problem.

Students at Berlin University Build Chess Game on Ethereum

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