A white knight is at c1, and the black king is at its starting position. White moves first, and tries to reach the black king, who will remain at its square. At each turn, the black king can sow a mine in any empty square. White wins if the knight reaches the King, and loses if it runs out of moves.

Who wins this game?

Hmmm...

My first instinct would be that the White Knight doesn't have a chance, but since my solution is fairly simple, and since this is a D3 puzzle, I'm probably making some simple mistake somewhere.

If the Black King stays where it starts, at E8, the White knight would take a minimum of five moves to reach him. To reach the King, the Knight would be required to land on one of four "perimeter" squares one Knight's-move away from the King. It is these squares that the King should focus on before worrying about anything else. The Knight can reach the perimeter in four moves.

The Knight could hit any of the four perimeter squares, but he couldn't hit either of the two side ones, C7 or G7 without obviously going towards that direction. The Knight could not be on any square that would allow him to reach both.

So... all the King would have to do would be to lay two mines on his two frontal squares, D6 and F6, and then lay a third mine on whichever side the Knight is heading towards, and finally his fourth mine on the last perimeter square. Now he is completely safe and can lay the rest of his mines at his own pace, knowing he'll have to completely trap the knight at some point.

Seems too easy. Wonder what I did wrong.

Edited on March 7, 2005, 9:20 am

Posted by Sam on 2005-03-07 09:13:47