Koji, along with Kenji and Taisuke, are among the few completely fictional characters in The Accidental Samurai. Bar Asher accompanied the three brave villagers on the trip from Izumo Province to Heian-Kyo (Kyoto). Not much is known about the lives of villagers from distant provinces during the Heian era. Koji is, of course, from a village near Izumo, where Bar Asher lands on the Hui, and he is very kind to Bar Asher. As explained in Fact of Fiction #19, which features Kenji, one of the few things we do know about farmers and villagers at that time is that they were subject to high taxes paid mostly in rice and also had to earn enough or grow enough to sustain themselves and their families. Therefore, the trip to Heian-Kyo, and the success of the trading there, was literally a life or death journey for Koji’s family and fellow villagers.
Yet, Koji is kind to Bar Asher and is quick to aid Bar Asher when he confronts the tax collector and his men. Bar Asher was under assault by 4 well trained soldiers and Koji though quickly and threw Bar Asher his shield. This enabled Bar Asher to defeat all four while withstanding blows from his two best trained opponents. Koji is also empathetic when Bar-Asher is saddened that he had to kill brave soldiers simply because of the tax collector’s huge ego an unwillingness to spare Koji’s village. Bar-Asher clearly values Koji, Kenji, and Taisuke, as friends.