Jack first met Yori at Niten Ichi Ryu, and the two soon started to get along well. Yori, along with Kiku displayed talent in Sensei Yamada's zen classes, which, in fact, was the only class that Yori actually liked.
Yori is scared to become a true samurai, and is fearful when he is accepted into The Circle of Three in The Way of the Dragon. He sees the silver lining when he is injured by a charging boar, since his injury would prevent him from participating in the Circle any further.
In the third book, Yori discovers a new skill- Kiaijutsu, the legendary skill of Sohei (fighting monks) that was taught to him by Sensei Yamada. This helps him gain some confidence in his skills as a warrior and he displays tremendous courage during the fight against Daimyo Kamakura.
During the Battle For Osaka Castle, Yori retreats along with the rest of Masamoto's forces as they are heavily outnumbered by Kamakura's Red Devils, but the castle gates are shut before he can reach the fortress and Yori is trapped outside on the battlefield. Jack and his friends take him for dead, however later it is revealed that Yori survived with the help of Sensei Yamada. Yori is seen at the end of the third book bidding farewell to Jack as he leaves for Nagasaki. Yori and Sensei Yamada then head on a pilgrimage to the Iga Ueno temple.
Yori makes a dramatic re-appearance in the Ring of Fire when he helps to defend Tamagashi Village against a bandit invasion with Jack.
In The Ring of Sky, Yori is believed to have been drowned during the storm by Jack after he is washed up on the beach alone.
Later, it is revealed that he in fact survived along with Jack's other friends. But, again, Jack thinks he is dead when Yori is stuck in the burning farmhouse.
At the end of the book he journeys to England with Jack and Akiko, looking forward to the prospect of exploring a new land.
Yori is described as being dimutive in stature, and is described as being "mousey," but he possesses great wisdom and intelligence, being Sensei Yamada's star pupil and finding his tricky riddles relatively easy to solve. Though he may seem timid he is capable of great courage and defends Jack.
Initially, Yori is shy and timid. But he is also capable of great courage and loyalty. In later books he is more aware of his courage and will defend his friends to the last.
Yori is the voice of wisdom on the group, taking after his mentor and friend Sensei Yamada.
- Koans - Yori is very good at pondering over and coming up with a plausible explanation for the various riddles Sesei Yamada gives the samurai students at Niten Ichi Ryu.
- Kiaijutsu Expert - at first Yori isn't very good at this but later on develops a great talent for it which comes in use later on in the series.
- Oragami- Yori is highly skilled in oragami, he believed that if you follded 1000 paper cranes you would be granted a wish so he did this and gave the 1000th crane to Jack before a duel.
As of the Ring of Fire, he wields a shakujo, a monks staff which can also be used as a weapon.