The Samurai Detectives: Volume 1 by Shotaro Ikenami

Shogun meets Sherlock Holmes! Over 24 million copies have been sold of this beloved samurai adventure.

It has been half a year since Akiyama Daijiro became a samurai; half a year since he left his father Kohei – once the most skilled swordsman in the land – to set up his own blade school by the cool of the river. Ever since, amid the swaying bamboo groves, he waits patiently for his first disciple.
But his serenity is soon disrupted by the visit of a mysterious samurai with an unhonourable offer: in exchange for a vast sum of gold, he must attack and injure the daughter of the Shogun’s most senior counsellor.

Troubled by the proposal, Daijiro, alongside his father and Mifuyu, a female warrior without match, soon set out into the underworld of Edo-era Japan to uncover the conspiracy, before quickly finding themselves embroiled in a series of increasingly perilous adventures . . .
Widely considered to be the greatest work by Shotaro Ikenami, the master of Japanese historical fiction, The Samurai Detectives is a twisting, page-turning portrayal of one of the most intriguing, evocative periods in the history of Japan.