A legendary story between a master blacksmith and his apprentice

Before we look at the history of Japanese blades, it’s good to share a legendary story that reflects Zen Buddhist teachings and the heart and soul behind the art of Japanese kitchen knives.

During the Kamakura period, there lived in Japan a swordsmith named Goro Nyudou Masamune, who was considered the greatest blacksmith in Japan. He had an apprentice named Muramasa, who later became a great swordsmith himself and founded his own school of sword-making.

One day, while Muramasa was still a student of Masamune, he challenged his master to a test — to see who could make the sharper sword.

The master and apprentice worked day and night, and when the swords were ready, they went to a small stream. The test was simple: they would place their swords in the stream, against the current, and observe which blade could cut through everything that floated downstream.

The apprentice’s sword, named “10,000 Cold Nights,” cut through everything that came its way — leaves, fish, and even the air around it seemed to be sliced. Muramasa’s sword impressed Master Masamune. Then Masamune placed his own sword in the stream to see how it would perform. His sword cut only the leaves that touched the blade but did not cut the fish.

The apprentice was proud that his sword appeared to outperform his master’s. But a Buddhist monk, who had been watching, came to them and explained what had happened:

“The first sword is certainly a fine blade. But it is an evil blade and thirsts for blood. It does not distinguish what or whom it cuts — be it heads or butterflies. In contrast, the second sword is nobler, for it does not harm the innocent or the undeserving.”

So through this story we see that a sword — or a kitchen knife — is not merely a tool for cutting. Instead, a good knife or sword must be guided by the right intention, heart, and spirit.