thumb|Yamato Takeru Later, when Suinin's grandson Prince Ousu (also known as Yamato Takeru) went to Ise to visit his aunt Yamatohime before going to conquer and pacify the eastern regions on the command of his father, Emperor Keikō, he was given the divine sword to protect him in times of peril. It eventually came in handy when Yamato Takeru was lured onto an open grassland by a treacherous chieftain, who then set fire to the grass to entrap him. Desperate, Yamato Takeru used the sword to cut the grass around him (a variant in the Shoki has the sword miraculously mow the grass of its own accord) and lit a counter-fire to keep the fire away. This incident explains the sword's name ("Grass Cutter"). On his way home from the east, Yamato Takeru – apparently blinded by hubris – left the Kusanagi in the care of his second wife, Miyazuhime of Owari, and went to confront the god of Mount Ibuki on his own. Without the sword's protection, he fell prey to the god's enchantment and became ill and died afterwards. Thus the Kusanagi stayed in Owari, where it was enshrined in the shrine of Atsuta.
thumb|Yamato Takeru Later, when Suinin's grandson Prince Ousu (also known as Yamato Takeru) went to Ise to visit his aunt Yamatohime before going to conquer and pacify the eastern regions on the command of his father, Emperor Keikō, he was given the divine sword to protect him in times of peril. It eventually came in handy when Yamato Takeru was lured onto an open grassland by a treacherous chieftain, who then set fire to the grass to entrap him. Desperate, Yamato Takeru used the sword to cut the grass around him (a variant in the Shoki has the sword miraculously mow the grass of its own accord) and lit a counter-fire to keep the fire away This incident explains the sword's name ("Grass Cutter"). On his way home from the east, Yamato Takeru – apparently blinded by hubris – left the Kusanagi in the care of his second wife, Miyazuhime of Owari, and went to confront the god of Mount Ibuki on his own. Without the sword's protection, he fell prey to the god's enchantment and became ill and died afterwards. Thus the Kusanagi stayed in Owari, where it was enshrined in the shrine of Atsuta.