Photo/IllutrationA tablet explaining the origin of “sangaku” math tablets is posted to the right of a sangaku for Question 1 at Todaiji temple in Nara. (Ryo Miyazaki)

  • Photo/Illustraion

NARA--Resurrecting a religious tradition from long ago, wooden tablets posing divine math questions for visitors have been posted in the Great Buddha Hall of Todaiji temple here.

The public is being challenged to submit solutions no later than Sept. 7.

The Mathematics Certification Institute of Japan (MCIJ), which offered the “sangaku” math tablets with two problems that have to do with Todaiji, will reward the best answers with certificates and prepaid Tosho Cards for books.

Sangaku refer to frames and tablets that were dedicated to Buddhist temples or Shinto shrines and carry arithmetic or mathematical questions and solutions thereto. They were used to present questions in the “wasan” school of mathematics, which flourished in Japan in the Edo Period (1603-1867).

Question 1 of the latter-day sangaku asks: if the Great Buddha were to sit in a bath up to his shoulders, how many liters of water would be needed for the bath? The information available for solving the problem includes a sitting height of 14.98 meters, and a length of 6.8 meters from the left knee to the ankle, of the Great Buddha.

Question 2 asks the radius, in kilometers, within which the sound of Todaiji’s big bell can be heard. The bell is assumed to have been struck by a group of eight people at midnight on Dec. 31, 2017. Provided information also includes a bell weight of 26.3 tons.

There is no unique answer to either of the problems. Applicants will be evaluated for their train of thinking that led to their solutions, the logicality and the originality of their imagination.

“A rote learning of predetermined solutions for taking exams leaves no room for the fun of thinking,” said Shunichi Amari, 82, the president of the MCIJ. “Mathematics is, at its very root, something very free.”

The MCIJ has designated Jan. 23, a date that contains the consecutive figures of 1, 2 and 3, as a “day for spreading the sangaku culture.” It has been offering math tablets to Todaiji on that date every year to invite people, in the words of MCIJ officials, to “experience the pleasure of thinking and the fun of solving problems.”

This year, the fourth time the tablets have been dedicated, the MCIJ has created new group awards for which schools and other entities are eligible.

Visit the MCIJ website at for details on the text of the questions and for submitting solutions. Call the MCIJ (03-5812-8340) for inquiries.