One of the random Forest events you will encounter is the old man at the mystical hut. Not to be confused with the lost old man, or the Forest monster Old Man. You can either knock on his door, or bang on it. Hitting the enter key instead of choosing one will automatically select the (K)nock option, which is rumored to have a 75% success rate. But then, so does (B)anging. If the old man is home, he will open a window and shout down to you, offering to teach you some Mystical arts if you can guess the number he's thinking. You can decline this guessing game, but that would be pure foolishness.