This novel shines a spotlight on the achievements of the historical figure Shibukawa Harumi (1639?1715), a brilliant go player, astronomer, and calendar maker. As the story opens, Harumi is 22, already with ten years' experience serving at Edo Castle (in what is now Tokyo) as the eldest son of the Kyoto-based Yasui family, one of the four houses appointed to instruct the Tokugawa shogun in the board game of go, which like noh is a required accomplishment for members of the warrior class. Harumi (who later changes his surname from Yasui to Shibukawa) has studied not only go but also mathematics and astronomy, yet is still surprised when he is suddenly ordered by shogunate senior councillor Sakai Tadakiyo to travel around the country to measure the angle of elevation of the north star. At this point in history?in Europe it is barely two decades since the death of the heliocentric astronomer Galileo Galilei?Japan still depends on a calendar it had adopted some eight centuries earlier from China, and Harumi's mission is to correct the considerable discrepancies that have since arisen. Given, however, that the prerogative over matters of time measurement traditionally rests with the emperor and the aristocracy, participation in the shogunate's calendar-revising scheme throws Harumi into the midst of a power struggle between the imperial court in Kyoto and the warrior regime in Edo. Some 15 months and 5,000 kilometers of travel later, Harumi returns with his data and takes charge of the calendar effort, succeeding two decades afterward in having the shogunate officially adopt Japan's first domestically developed calendar. Ubukata says he conceived the idea behind this novel when he was 16, and his tenacious commitment to the project has paid off in a blockbuster entertainment work about the thrill of intellectual inquiry.