Tenchi Meisatsu

In 1661, Yasui Santetsu, a member of the prestigious Yasui House, begins to question his family's esteemed position within the Four Houses of Go. Outside of the Go house, he assumes the alias Shibukawa Harumi, and his true passion lies in the realms of mathematics and astronomy. Harumi is consumed by the task of creating a revised Japanese calendar, driven by his desire to modernize the country's outdated system. The story is inspired by the life of the actual astronomer and calendar reformer Shibukawa Harumi (1639-1715), who lived during an era where the Japanese relied on the ancient Chinese lunar-solar Xuan-ming calendar, unchanged for nearly 800 years. As a result, the calendar had accumulated a two-day delay in the winter solstice, prompting Harumi to develop a revised system based on his meticulous astronomical observations.