Until the 8th century, Japanese swords were straight double-edged blades (chokuto), similar to Chinese swords. Amakuni Yasatsuna, together with his son, was the first to create the first long single-edged curved blade (tachi) around 700 AD. The story goes ike this: On a gloomy day when the warriors were returning from a big battle, the soldiers and the emperor ignored Amakuni and did not greet him. He was saddened but also noticed that most of them were carrying Amakuni’s swords that were damaged and broken. He and his son took an oath to make the best sword possible. They knew that they had to improve the way the swords were forged and use stronger metals. They used the best iron sand ore and turned it into steel. They prayed the shinto gods for 7 days and after 7 days Amakuni had a dream where he had seen a curved shiny blade which had only one edge. He and his son worked 31 days and nights trying to make a sword similar to what Amakuni saw in his dream. They made 31 of them and gave them to the emperor. The next spring, the emperors’ soldiers used the new swords in a major war and none of them broke. Amakuni was a hero and the legend goes that amakuni finally became immortal because of the blood shed from the blades he made.