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As we all know, Houdini is very good at coming out on top against improbable odds! And oh boy are the odds improbable. For his next great performance, he claims he can play simultaneous chess games against the 8 best chess players in the world. Although he is a very smart man in other ways, he is a mediocre chess player at best.

8 chess tables are set in the room, and Houdini gets to play the white pieces in half the games. For this event, he scores 0 points for every loss, 1 point for every draw and 2 points for every win. He makes the ambitious claim:

I will score no less than 8 points

After all the games have been played, Houdini has scored, in fact, exactly 8 points. How did he do it?

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  • $\begingroup$ Is this a trick question? $\endgroup$ Feb 9, 2015 at 23:15
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    $\begingroup$ obviously there is a "trick" involved, but I wouldn't call it a trick question. there is no crazy nonsense in the answer, no play on words or such shenanigans. $\endgroup$ Feb 9, 2015 at 23:20
  • $\begingroup$ Can you clarify "the white pieces in half the games"? $\endgroup$ Feb 9, 2015 at 23:34
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    $\begingroup$ I assume you took this puzzle from this popular video: youtube.com/watch?v=evZmpsl3jI0 $\endgroup$ Feb 10, 2015 at 1:30
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    $\begingroup$ Aside: Houdini is actually one of the strongest chess engines in the world. $\endgroup$
    – geometrian
    Feb 10, 2015 at 2:44

2 Answers 2

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Houdini cleverly paired up each game in which he played black with a game in which he played white. He then simply copied the moves played by his opponent to the corresponding game.

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    $\begingroup$ +1. Just a note that Houdini also has to make sure that he saw the grandmasters' who play white moves first before playing his own white moves. $\endgroup$
    – justhalf
    Feb 10, 2015 at 1:58
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    $\begingroup$ It wouldn't work in reality, in real simultaneous chess he must make a move at the first board before he's allowed to move to the next, and his opponents only have to make their move when he shows up at their board. $\endgroup$ Feb 10, 2015 at 11:19
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    $\begingroup$ The key is that Houdini's "opponents" are essentially playing against each other. The two opponent's moves are different, but that is because they are playing different colors. $\endgroup$
    – singletee
    Feb 10, 2015 at 16:14
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    $\begingroup$ @FreeAsInBeer Let's say he's playing White on board A and Black on board B. By copying all the black moves from board A (his opponent's) as using them as his moves on board B - and vice versa for the white moves - he's basically letting his opponents play each other. It's like chess by mail except that Houdini is transcribing the moves instead of them being written down. $\endgroup$ Feb 10, 2015 at 16:15
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    $\begingroup$ @KSmarts In order for this trick to work he has to play black first. $\endgroup$
    – singletee
    Feb 10, 2015 at 21:15
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He could have won 4 games and lost 4 (4x2 + 4x0 = 8), or drew all 8 (8x1 = 8).

Is there more to the question? I feel like I'm missing something..

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    $\begingroup$ this is not solving the puzzle at all! you missed the question. simultaneous chess in incredibly hard. How did Houdini managed to not get crushed in all 8 games? how did he score a single point? how did he score 8? $\endgroup$ Feb 9, 2015 at 23:33
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    $\begingroup$ I think it was still a valid answer, even if it's not the right one - before the edit there was nothing to suggest that he'd be expected to lose. $\endgroup$
    – ladyofcats
    Feb 10, 2015 at 1:22
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    $\begingroup$ :( Should I delete my answer? The question asked how 8 points were scored, and with the original wording I couldn't see why getting this score should be hard. $\endgroup$
    – ladyofcats
    Feb 11, 2015 at 0:41
  • $\begingroup$ @Vajura I think this stackexchange is about having a friendly community to work on creating and solving puzzles, which to me would include showing how I interpret a puzzle I haven't come across before to help the creator refine their wording. $\endgroup$
    – ladyofcats
    Feb 11, 2015 at 0:53
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    $\begingroup$ @ladyofcats If you have a question about the puzzle or feel it could be clarified, the appropriate place to do so is in the question comments. Answers are only for answering the question. $\endgroup$
    – singletee
    Feb 13, 2015 at 17:59

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