There is no legend of the sword. Masamune was a man who was a sword maker who made a blade that did not cut leaves.
The legend goes like this.
Masamune and his rival, Muramasa, were trying to impress their teacher. The rival made a blade so sharp when placed into the river every leaf that passed by it was sliced clean in two. The blade was named 10,000 winter nights.
Masamune's blade when placed in the river cut not a single leaf. And it was named Tender Hands.
The teacher claimed Masamune the winner and when Muramasa asked why when his blade cut everything and Masamune's cut nothing the teacher said. "Your sword was a fine sword, but an evil blood thirsty blade that did not care what it cut. Masamun Frankly Masamune did not even make Katana, he was around before the Katana, he made blades called Tachi, which would be more like Egyptian Kopis.
So there was NEVER a sword called the Masamune. If you want a blade from Japanese legend use the Kusanagi (The Grass Cutter). Though it was not a Katana, it was a Tsurugi which would be like a Chinese Jian. One of the Imperial Regalia of Japan. It was used by the God of the Gather Storms, and he stole it from the tail of an 8-headed dragon he killed by getting it too drunk to fight back. How cool is that!
