Watch Tenchi: The Samurai Astronomer for Free: How to Stream the Movie Online at 123Movies. . A chronicle of the life of Yasui Santetsu, a 17th century master of go who turned his attention to astronomy and created a new calendar for Japan. Based on the life of Santetsu Yasui (December 27, 1639-November 1, 1715), appointed as the first official astronomer in the Edo Period and would go on to create the Jokyo calendar at the imperial request.