Jinkōki (塵劫記, じんこうき, Permanent Mathematics) is a three-volume work on Japanese mathematics, first edited and published by Yoshida Mitsuyoshi in 1627. Over his lifetime, Mitsuyoshi revised Jinkōki several times. The edition released in the eleventh year of the Kan'ei era (1641) became particularly widespread. The last version personally published by Mitsuyoshi was the Idai (井大), which came out in the eighteenth year of the Kan'ei (1634). Subsequent to that, various editions of Jinkōki were released, one of which includes Shinpen Jinkōki (新編塵劫記). Jinkōki is one of the most popular and influential Japanese mathematics books in history, having influenced Seki Takakazu, Kaibara Ekken, and many other later Japanese mathematicians. It is partly based on the works of Yuan dynasty mathematicians in China. Source: Wikipedia (en)