Samurai Executioner, known in Japan as Kubikiri Asa (首斬り朝), is a 10-volume manga created by writer Kazuo Koike and artist Goseki Kojima, the same team that created the popular Lone Wolf and Cub series. The series was first serialized in Japan, from 1972 to 1976. Samurai Executioner is set earlier than Lone Wolf and Cub, with the main character of the former series appearing in a chapter of the latter.
The story is set in the Edo period of feudal Japan. It revolves around Yamada Asaemon (山田 朝右衞門, Yamada Asaemon), nicknamed Kubikiri-Asa (literally "Neck-chopper Asa", often translated as "Decapitator Asaemon"), a rōnin who is responsible for testing new swords for the shogun. The character is based on a real-life line of sword-testers who served the Tokugawa Shogunate up to the early 19th century. He is also frequently called upon to perform executions.
Many of the stories focus not on Asaemon, but on several of the people he meets in the course of his work. More often than not they are the stories of the criminals he executes, told as their last words before receiving the fatal stroke. As with Lone Wolf and Cub's Ogami Itto, such encounters often give Asa pause for thought.