"A hardworking son who lived with his aged parents grieved that he was unable even to give his father sake to drink because they remained poor no matter how hard he worked. One day, when he was cutting down trees in the forest, he heard the sound of rushing water. Searching for the source of the sound, he came upon a small waterfall. When he cupped some of the water in his hands and took a drink, he discovered that it was sake. In his surprise and delight, he filled his gourd from the waterfall and took it home. Overjoyed, his father drank the gourd dry with his neighbor. Word of the waterfall spread overnight, and the next moring, many of the villagers hiked into the forest to get sake from it themselves. What they found in the waterfall, however, was only water. Believing that they had been deceived by him, the villagers became angry with the son, but all of the water he took from the fall turned into sake. The story reached the ears of the Emperor, who even changed the name of the period in honor of the son's devotion to his parents." (Kyoto University of Foreign Studies,
https://www.kufs.ac.jp/toshokan/chirimenbon/b_21.html)