# Magician wins in chess against experts. How did he do this?

I just saw this video of magician Derren Brown playing simultanous chess against 9 very skilled players.

The video can be seen here
Here is a summary:

Before the match he gave one player an envelope.

He wins the match 4 - 3 with two draws.

He asks the player for the envelope, opens it, and on it is written a number. The digits in this number corresponds to the number of pieces the players have left. (With one mistake.)

In the end he explains that the reason he did so well against the first 8 players is that he copied their moves, so they really played against each other. Simple enough.

But how in the world did he make the number of pieces fit? And how did he beat the ninth player? Is it all a setup?

He used the chess masters to play against each other by memorizing their moves. For instance, he memorized the chessmaster at table 6’s move and when he went to table 3, he reversed the game and made that move himself against number 3.

and the ninth player he probably really played on his own.

I wish I had an edit button, because I didn’t see your last two sentences of your post. Either that or you edited it. Sorry about that, I’m too quick to respond sometimes.

I happen to be the man to answer this.

Derren did three tricks:

• as he said, he arranged that 8 of the chess players played **against each other ** (including all the grandmasters). He did this by putting all the players in a circle facing outward, then asking the players with White to make a move, then making those 4 moves against the corresponding Black players, memorising their moves and transferring those moves back to the corresponding White players (hope that makes sense).
This does require Derren to remember 4 chess moves at a time (and over a hundred during the display), and he didn’t make a single mistake! (he did hesitate once, but got it right)

• he beat the weakest player. I have no idea how he did this. I can assure you that he played like a 2200 rated expert, but he clearly isn’t.
There was a strong player in the TV program credits, who could have fed Derren the moves. But Derren didn’t have an earpiece and nobody spoke to him during the display (which was a single-take lasting over 3 hours )

• he gave one player an empty envelope at the start. Then he took a short break after the display, counted the pieces, made a duplicate envelope and performed a switch (he arranged for a distraction by the crew at the critical moment). I assure you he’s fast!

I’d like to add that Derren is a gentleman, because at the end he could just have shot off. instead he chatted to the players, thanked them for their time and signed autographs.

What a coincidence! I opened this thread to mention the existence of the precise trick the magician pulled off: The scoundrel acting as a proxy such that the good players actually play against each other, thus being able to ‘beat’ people far out of his league.

Bruce Schneier mentions this precise method in Applied Cryptography (second edition), pg. 109, as a possible way to break some insecure zero-knowledge proofs of identity.

Just a nitpick - you can only get 50% with this method (win + loss; or two draws).

I didnt see anything about a distraction. Does that mean that he performed the trick at a point that I as a viewer don’t see? Because that sucks.

Well all magic is trickery.

Nobody present saw him switch the envelopes (and he was being closely watched!).
Therefore it seems fair to me that the TV program allowed him to produce his ‘predictions’.

There are a great many ways he could have gotten communication from a confederate. The simplest would be to just have the moves shown on a teleprompter behind the camera (I’m assuming only one camera, since you said it was a single take). If he wanted to be more subtle, he could have worked out a code with his confederate involving hand signals, taps on the floor, or “oohs” and “aahs”. He could have had a radio hidden in his shoes, that was wired to buzz him signals. Or the ninth player could himself have been a stooge, and thrown the game.

I think he just beat him straight up. The guy didn’t exactly have that strong of credentials as a chess player. He was merely the president of some chess club. That doesn’t necessarily make him a top notch player, and it’s quite possible the magician is simply a better player.

There were four cameras. Two were on tripods, one was hand-held and the other was one of those that move on a boom, but can also rotate under remote control.
Derren appeared to ignore the cameras (but that’s just what professionals do, isn’t it?).
Perhaps there could have been a separate TV monitor out of the players’ sight with a chess board shown on it - but the neighbouring players might have seen it…

The studio was very quiet throughout.

The game could have been pre-arranged. But it lasted about 30 moves, and I think that would be a real strain for a non-player, given that he’s carrying 8 new moves each circuit.

I’m still baffled.

The ninth player was president of some University club. He had an ELO rating of about 1800.

(Please excuse me making some claims here. :o )

The ninth player did OK - there were no blunders. Instead Derren took him out playing like a 2200*. (It was a fine attack using opposite-colour bishops, converting into an endgame a couple of pawns up.)
If Derren was a 2200, he would be known by the English chess community**.

*I’m a English national chess coach and claim to be able to assess playing strength to some degree.

** there are about 120 players of 2200 strength in England, all on the rating list (published annually). I’ve been in the room with all of them (either at the National Championships or the National League).
Also if we had a celebrity playing chess regularly, it would be jolly exciting for us nerdy geeks!

I am so impressed by the depth as well as the breadth of the expertise people like you bring to the Straight Dope.
Now the only thing is to figure out which of your 2200-level colleagues he played most like…

IMHO, copying the opponent’s moves in Chess won’t work unless you’ve set the initial array up incorrectly.

Plus, the opponent might question why you’re capturing his Queen with yours after he’s captured your Queen.

I think the idea is that you copy your other oponents moves so that they are essentially playing each other.

Well as I mentioned there was a suitable chap in the credits.
I just can’t work out how he communicated with Derren…

Suppose you’re Derren. You go to a board where you have the Black pieces and note your opponent’s move (say e2-e4). Instead of replying as normal, you stroll round to the opposite side of the circle and play e2-e4 on a board where you have White. Noting this opponent’s response (say c7-c5), you return to the first board and play c7-c5 yourself.
As you can see, all Derren is doing is acting as a transmitter of moves. Provided he remembers all the moves correctly, he must score precisely 50% (either a win + loss, or 2 draws).

In the display, the top rated player was Grandmaster Julian Hodgson. He likes to play the Trompovsky opening as White, even though most other top players don’t.
So (if I rmeember correctly) Grandmaster Chris Ward is Black. He gets the first move d2-d4, replies Ng8-f6 and grimaces when Bc1-g5 (the Trompovsky opening) appears - since he’s obviously Black against the top seed.

I didn’t watch the whole video, so I have to ask, did we see someone actually examine Derren’s ear to make sure there wasn’t an earpiece? At the beginning, he just bent down and pointed at his ears to the chess masters for about a second. I didn’t see anyone actually crawl inside his ears with a Q-Tip for a closer look.

This used to be a favorite trick of Uri Gellar’s. He’d show you a fork really quickly and tell you how hard it was, and then he’d bend it. In the end, you only had Uri’s word that it was unbendable by conventional means.