Photos show the wooden tablet unearthed at the Heijo Palace site in Nara. (Photo courtesy of the Nara National Research Institute)
NARA — An ancient wooden tablet bearing multiplication sums has been found among a large number of unearthed tablets that are believed to date back to the late Nara Period (710-784).
The tablet, whose discovery was reported Dec. 3 in a publication of the Nara National Research Institute for Cultural Properties, was among those unearthed in 2008 in an administrative district at the site of the remains of the Heijo Palace in Nara. It is believed that the wooden tablet, or “mokkan,” was used by an official for times table practice.
“The characters are not that tidy, and it was probably used by a lower-ranked official to diligently study the multiplication table,” said institute official Akihiro Watanabe. “In the area there is a mixture of wooden tablets bearing the names of high-ranking officials in beautiful block script characters and tablets bearing poorly written characters, which is interesting.”
The tablet measures 16.3 centimeters long and 1.5 centimeters wide. On one side it bears part of the sum of “3×9=27,” together with the sums “2×9=18” and “1×9=9.” On the reverse side are “5×8=40,” “4×8=32,” and part of the sum “3×8=24.”
A large number of wooden tablets were found in the area in a hole measuring about 6 meters in diameter that had been used to discard waste. Some of them bore the era name “Hoki,” corresponding to the years between 770 and 781, and it is believed that they were discarded toward the end of the Nara Period.
The rhythmic memorization method of the 9×9 times table is believed to have originated during China’s Spring and Autumn Period between 770 B.C. and 403 B.C. It appeared in Japan in a textbook for children titled “Kuchizusami,” written during the Heian Period in 970.
About 30 examples of such wooden tablets have been discovered across Japan, including early 9th century specimens unearthed at the Nyogamori archaeological site in Toyooka, Hyogo Prefecture.
(Mainichi Japan) December 6, 2010