The first article on Konnyaku came in Genjun's Wamei Ruijusho (931-937), the oldest Japanese encyclopedia. There are also many references to Konnyaku in historical Japanese literature such as proverbs, Tanka (Japanese poems of thirty one syllables; in 5-7-5-7-7 syllabic form), Haiku (Japanese poems of seventeen syllables; in 5-7-5 syllabic form), Senryu (satirical seventeen-syllable Japanese poems; 5-7-5 syllabic form) and so on. Konnyaku is indispensable to modern Japanese dining tables and loved as the taste of home cooking. There are many folk stories and legends connected with Konnyaku in Japan. Most of them try to explain how Konnyaku is good for our health.
The story of a Buddhist monkThere is a story of a Japanese monk who loved Konnyaku in a book called Hagakure (around 1716). Naoshige Nabeshima was the founder of the domain of Saga. When he was young, he was trained in a temple. After his training at the temple, he asked the monk what he wanted as a reward for his teaching. Then, the wise Buddhist monk told Naoshige that he wanted to eat Konnyaku every day as long as he lived. Thereafter, Naoshige sent Konnyaku to the monk every other day and the monk lived longer and ate Konnyaku everyday until he died, as he wished.
The story of Kuzaemon's wifeWhen Hideyoshi Toyotomi (1536-1598,. a famous military commander in Azuchimomoyama period) was building the Hizen Nagoya castle, one of the stonecutters named Kuzaemon got a severe stomachache and fell into a critical condition. Then his wife prayed to God for her husband's recovery by pouring cold water upon herself. (Praying for God by pouring cold water was regarded as one of the most severe ways to pray for help to God and it was intended to show God how strongly the person wished for his help.) Then, God listened to her wish because of her piety and her strong love for her husband.
While she was sleeping, God came to her and told her, "Your husband has a stone in his body. I will give you my secret medicine because you are very religious." When she woke up the next morning, she found a Konnyaku potato next to her pillow. She made Konnyaku from it and gave it to her husband, Kuzaemon.
After eating Konnyaku, Kuzaemon miraculously recovered and returned to the construction work on the castle. Many Daimyo (feudal lords) who heard this story tried to spread the use of Konnyaku in their territories and Konnyaku became more widespread and more popular.