This article introduces a writing format, the ‘template table’ (suanshi, ) that was designed to guide the process of calendrical astronomical calculations in early modern China. In conjunction with another kind of text, known as ‘detailed procedures’ (xicao, ), users could perform calculations easily by operating the ‘template table’ and extracting data from given numerical tables. This method, that not only normalized the use of numerical tables but also linked instructions with the corresponding tables in computational practices, became widespread from the Ming period (1368–1644) onwards. Wanting to acquire this computational regimen, the Joseon court of Korea (1392–1897) even sent skilled officers to China to learn it secretly. The circulation of the template method beyond China suggests its significance. The article also discusses the advantages and disadvantages of using this method.