Sanyo-ki (the Calculation Manual) (算用記)

"Sanyo-ki" (the Calculation Manual) is the oldest book on Wasan (Japanese mathematics) extant in Japan, however, the author is unknown. The date it was published is also unknown but is estimated to be sometime between the Azuchi-Momoyama Period and the early Edo Period. "Warizan sho" (The Book of Division) by Shigeyoshi MORI published in 1622 has a description which seems to criticize "Sanyo-ki" as being too difficult to understand, so the latter should be older than the former. This book introduces calculation with an abacus and describes how to calculate volume and interest rate as well as the method for surveying. This book is regarded as the starting point of the history of Japanese mathematics. The only extant book is in the collection of Shajidai-bunko at Ryukoku University.