There is a myth（神话） that grandmasters can see ten, fifteen, twenty moves（动） ahead（在前）. And it's a great myth because I'm a grandmaster and it makes me look like a super（特级的） freakin' genius（天才）. But the truth（真理） is, in just the first four moves（动）, there are three hundred and eighteen billion ways you could play. Now（现在） that'd be cool if I could pull that off, but grandmasters just can't. It's too much. So we use different techniques（技巧） to be able to look ahead（在前）.

  And some of these techniques include chunking（大块）, which means taking a group of a chess position and seeing what possibilities can come from just that group. Or pattern recognition（认出）, which is just going over a lot of positions that look very similarly（类似地） and extrapolating truths（真理） from that. The stepping stone method, which is to take a position, freeze（冻） it in your mind, and go from there to guess the next position. But one of my favorites that I love to solve these kind of chess puzzles（难题） is called retrograde analysis（分析）. And what you do with retrograde analysis is that in order to look ahead, it pays to look backwards（倒）. Now, why is this so useful?

  Well, in chess, it's a very complicated（复杂的） case. You've got all these chess pieces, there's 32 pieces, but after five moves, the position starts to evolve（发展） a little bit. And then the game starts to go on and you see the chess position get a little simpler and a little bit simpler and less pieces on the board. Until finally, in this case, a game that I played in a tournament（比赛） in Foxwoods, it gets to something like this. When great players play, it often gets to something like this. You don't see like（喜欢） some easy early checkmate, grandmasters see through all that stuff（材料）.

  What you see is some end game, something really, really simple. And we like to study things like this, grandmasters do, so that if we get to them, we know how to play them cold, but also so that we can steer（驾驶） the position that's in front of us, the more complex（复杂的） ones you saw earlier, to something this easy, something this simple.