Im just curious how you know you are really playing someone legit when you are playing chess? I see the same people winning in the results, and wonder if they just start up a game of chessmaster, then choose the option to play against Bobby Fisher (Old Chessmaster lol). Now that they are playing against B F, they could just enter whatever move you make as their own, and then use Bobby Fishers move as theirs against you. Not trying to accuse anyone of doing this, but what are your guarantees that people arn't, and how could u know if they were?

The best answer is to ask Bobby Fisher or ask me privately.

You won't know at all.

The same used to occur to me regarding postal chess, (two people agree to play, one makes a moves, seals it in an envelope and sends it off to his opponent. It continued for months until there was a winner).

The only surefire way is to play someone live I guess, in tournaments or league matches.

The truth is we have no way of knowing for sure, however all of the people who are playing in the tournament have their own distinct styles and each have lost at least one game; as Lotus mentioned the only way to guarantee that an opponent isn't cheating is to play them live, face to face.

I think there is a way to doubt a player for cheating.
They might played game one on their own then use a software next or even on middle games,
they can consult online chess moves.
But...if you are going to study all their games and noticed they are average players, then suddenly
they are going to pull out a Grandmaster move, you begin to doubt.
The only way really to find out is to face them live.
I'm pretty sure...Saruman's games are done by himself. (not because he's the boss here)

You can't know, and based on my experience between playing in real life and playing people online, I'm sure the rate of that happening is quite high.

It's an honor system really.

And just a tip.. The real Bobby Fischer would have very easily beat the chessmaster Bobby Fischer .

There's no way to know, in the end its all coming down to trust. Which unfortunately is not much to go on I know, but as someone else says a good way to check is if they start making moves that are simply above their previous level without any evidence of gradual change (although its not always the case, elfstone who's a decent player but on in the top 5 here, has on two occassions come close to beating me - in fact once she had me beaten, but I'm sorry to say I offered a draw in desperation and she accepted not realising she was only five moves away from a forced checkmate - I've always felt I sole that draw from her and if Elf's reading this I'm sorry for that and I'll amit that despite the draw it says on the record, you beat me that match).

Although given the number of months it can take to finish a tournment, thats a lot of time for someone who's cheating to win to invest - why bother.