Umi no Mizu wa Naze Karai

why is the sea water salty - When a poor, yet honest, man rescues an old man who has fallen off a log bridge, the little people of the forest give him a "Mortar of Treasures" that will grant any item that a person desires. The man uses the mortar to become the richest person in the village. But the man's greedy brother steals the mortar and, determined to enjoy all the luxuries by himself, climbs into a rowing boat and heads for an isolated island. On the way, however, he asks for salt from the mortar, but then cannot figure out how to stop it. Finally, the boat sinks under the weight of all the salt, and the mortar sinks to the bottom of the sea where it is pouring out salt to this day.