REMIND ME AGAIN, he said, HOW THE LITTLE HORSE-SHAPED ONES MOVE.
Death, on symbolic last games, in “Small Gods” by Terry Pratchett
I recently stumbled upon a nice chess problem in a mini-game in “Watch Dogs”.
You are white and you only move your figures (black figures remain where they are). Using only the legal moves of the figures, you have to remove all black figures with the least amount of moves. It’s possible to do it in 12 moves — which is the first strong hint. The bishop (E8) can move only diagonally, the tower (D1) only horizontally and vertically.
Even if you are not interested in chess and don’t normally play it, try it.
It took me a long time to solve this problem, and I’m not sure whether my solution is the only one with 12 moves. But I guess so, because this problem has one quality that makes it extremely hard.
It’s already described in the title of this posting — you must not move the bishop. Unless I’ve missed something, [update, see comments: almost] any move of the bishop results in a solution with more than 12 moves. And that makes this problem extremely hard, because the bishop is part of the game, it’s on the board, you had to use all pieces in all prior chess puzzles. And now, you have a problem where you have to ignore something that does seem essential.
Extremely clever problem due to this distraction, and in general a good tip for finding the best solution. Try to do it with less — and ignore things you have, even if they seem essential.