|Portrayed by||Cary-Hiroyuki Tagawa|
|First appearance||The Line|
|Other relatives||Yumi (great great granddaughter)|
The swordsmith is Yaeko's father. He lived in the 17th century.
Near Otsu, Japan in the year 1671, Hiro says that according to the stories he heard as a child, Kensei will take the daughter of the swordsmith as his princess. Later, Yaeko takes Kensei's sword and says that her father created the weapon. Whitebeard captures the swordsmith after raiding Otsu, and Yaeko vows to save him.
Yaeko fights with a number of swordsmen accusing them of not being worthy of the title Samurai. The leader tells Yaeko that he needs her father alive, but doesn't need her. After Hiro rescues her in the Battle of Twelve Swords, he promises to rescue Yaeko's father.
The swordsmith is found in Whitebeard's camp at Kiso Mountain by Kensei, Yaeko, and Hiro. They are about to rescue him but he tells them he was coerced into showing Whitebeard how to make guns so Whitebeard can overthrow the Emperor. Hiro and Kensei make the plan to go back to destroy the guns, and they attempt to escape the camp. They are successful, but later Kensei betrays his friends and the swordsmith is once again held captive by Whitebeard.
In Chapter 4, Part 2, "Kensei and the Dragon", Professor Donna Dorn and Professor Karen Chamberlin document that Yaeko was the daughter of a swordsmith. Dorn adds that the swordsmith was "much admired".
Please refer to Theory:Swordsmith for fan-created theories and other speculation.