It is a sword made by Kunihiro Horikawa, a swordsmith from the Azuchi-Momoyama period, and is a copy of "this work Nagayoshi" by Bizen Osafune Nagayoshi during the Nanbokucho period. The sword was copied and struck at the request of Ashikaga Castle owner Akinaga Nagao, but the result is excellent, and it is said to be the masterpiece of Kunihiro Horikawa. Compared to "Choyoshi of this work", the shape of the peak and the positional relationship of the gutter tip are accurate, but the overall shape including the warp is not very similar, and it is said that the result exceeds the main song. Although it is a sword with a strange name, it is said that Jingoemon Ishihara, a ronin of the Odawara Hojo clan, cut down a mountain eater who eats people, so it was called "Yamanbagiri". As of 2020, this is the only case of a sword in which both the main song and the copy are important cultural properties.