Originally posted by vivify
If there was a piece which moved like the king did, I've always thought it would make a great defensive tool. Based my experience with endgames, the King's a rather sluggish peice if you need to rely on it for offense. However, I do agree that it's possibly the peice to get around tight pawn defense, since it has the best freedom of movement, aside of from the queen.
And yet, experts generally agree that in the endgame, when it does not have to hide in a corner, it has an attacking power only little less than a rook, and more than the average minor piece. It may not be fast, but it covers everything around it.
For comparison (a trivial one, but you might get some idea): you can't mate a lone king with any single piece (i.e., not using your king to help), not even a queen. You can mate with a queen and any other single piece, even a pawn if it's well-placed. Without queens, you can mate with a rook and a rook, or a rook and a king, but not with a rook and a minor piece (try it; they don't cover enough squares), and a rook and a pawn only works by promoting the pawn. So in that case, a king is worth as much as a rook, and more than a bishop or knight.