View Full Version : Anzan: mental calculators

John Lindsey
31st October 2000, 18:06
Japanese Adding Technique Survives

By GINNY PARKER, Associated Press Writer

KYOTO, Japan (AP) - The contestants sit hunched over bare tables, some in sweatshirts, some in neckties. A small audience watches quietly, while judges pace the floor in wait for a response.

Suddenly, a teenager's hand shoots up and a shout breaks the silence. ``Done!'' he calls out, and passes his answer sheet to a moderator.

Within seconds, Hiroaki Tsuchiya has multiplied - in his head - a list of numbers that would make an accountant's head spin. How does he do it? On an imaginary abacus, just as merchants, students and others have done throughout Asia for centuries.

Today, despite computers and calculators, the technique survives as a strenuous workout for the brain. Teachers say almost anyone can master it if they start young, although it takes hours of practice, mental dexterity and Herculean powers of concentration.

``If you space out, you lose,'' said Tsuchiya, who at age 13 recently became the youngest winner of a Kyoto tournament where Japan's best mental mathematicians display their amazing feats.

Tsuchiya, for example, takes only a few moments to solve a problem like 992.587318 divided by 5,647.723. And he has to go to the final digit of the answer: 0.17575000013279688115015555826658.

Called ``anzan,'' which translates roughly as ``mental calculation,'' the technique springs from an age when the easiest way to work with large numbers was to use an abacus, a manual calculator introduced to Japan from China in the 1500s.

The box-shaped instrument is made of beads that serve as counters, which users push back and forth along metal rods, clicking their way through cube roots, addition and subtraction, long division.

But skilled abacus users often find it easier to just imagine the beads rather than physically move them.

This is anzan, and those who master it can work faster than a clerk on an adding machine.

Read the full story at: http://dailynews.yahoo.com/h/ap/20001030/wl/japan_amazing_arithmetic_1.html