Why is the Sea Water Salty?
海の水はなぜからい
A poor but honest man rescues an old man who has fallen off a log bridge. As a reward, the little people of the forest give him a magical mortar that can produce any item he desires. Using it, he becomes the wealthiest person in his village.
His greedy brother steals the mortar and sets off alone in a rowboat to an isolated island, hoping to enjoy endless riches. When he demands salt from the mortar, he cannot stop it from pouring out. The boat sinks under the weight of the salt, and the mortar falls to the bottom of the sea, where it continues to produce salt to this day.