There is a famous Japanese joke that goes something like this...

"Once upon a time there was a great Buddhist priest named Ikkyu, whose fame spread far and wide for his enlightened solutions to peoples' problems. Finally, Ikkyu became so famous that words of his deeds reached the ears of the great Lord, who summoned Ikkyu to his mighty castle.

Upon learning of the summons, Ikkyu proceeded over hill and dale until at last he arrived at the main gates of the castle. In front of the gates was a river, with a bridge across it, and in front of the bridge was a sign which said:

BEWARE: Walking on the bridge is forbidden, by order of the Lord.

Ikkyu paused, thought for a moment, and then promptly walked across the bridge and through the gates. When Ikkyu came before the Lord, the Lord was astonished. "I have forbidden walking on the bridge!" he said, "How did you cross the river?"

"It was no problem," Ikkyu replied. "I simply walked down the center of the bridge."

The key to understanding this strange story is a Japanese pun that is not at all funny, but at least is a pun. It turns out that the Japanese word for bridge, "hashi," is pronounced the same as the Japanese word for edge, which is also "hashi." Thus by walking down the center of the bridge, Ikkyu obeyed the Lord's command to "not walk on the edge." (The kanji for "edge" (端) is different from the kanji for "bridge" (橋), however, so apparently the sign in question was written in hiragana).