Tuesday 28 February 2023

Brain Training Japanese-style: Flash Arithmetic and the Soroban (Japanese abacus)

Local evacuation site in case of earthquake
We've had some pretty cold days and even some snow - unusual for Tokyo - since I last wrote, and temperatures are very much up and down at the moment. News-wise there's been a lot of sympathy for the victims of the earthquake in Turkey and Syria, due both to Japan's own experience (the March 2011 Tohoku quake was the strongest in Japan's recorded history and the 4th biggest worldwide) and its close historical affinity with Turkey. Last month, the high court ruled that the Tokyo Electric Power (TEPCO) executives could not have predicted the massive tsunami that led to the Fukushima nuclear facility meltdown, even though a 2002 government report had actually estimated even higher waves. Government scientists tend to be very accurate with their numbers; the latest calculations give a 70% chance of a mega quake hitting Tokyo before 2050. 

Speaking of calculations, Japanese have long come near the top in mathematics in international rankings (PISA rankings here). For those wondering why countries like Japan, Korea, and China perform so well in maths, you need look no further than the humble abacus, called soroban (そろばん)in Japanese. Walking through the neighbourhood the other day, I spotted a sign board outside a house advertising soroban tutoring. The key sales pitch was the way abacus-style mental arithmetic (anzan=暗算, literally "dark calculation") promotes brain development and mental agility by stimulating both left (language) and right (visual) sides of the brain. Indeed, those proficient in the soroban become able to complete mental arithmetic remarkably quickly in the their head by visualising an imaginary abacus. There are even "flash" mental arithmetic competitions in which competitors instantly add, subtract, multiply, or divide numbers of 1 to 3 digits that flash on a screen (video here - check out the speed of the guy around the one minute mark!). It is no surprise that in the mental calculation world championship - held every two years in Germany - Japan has consistently featured in the top three. And these guys are fast: a famous contest between a Japanese soroban user and an American calculator user in 1946 resulted in the abacus scoring a "decisive victory" and beating the machine in both speed and accuracy in everything but multiplication.

Derived from the Chinese suanpan, the soroban has been used in Japanese schools for some 500 years, though with the spread of electronic calculators it is no longer a compulsory subject (it still remains common in elementary schools as a way to visualise and grasp basic mathematical concepts). As the picture shows, the modern soroban - which interestingly is the same as the roman abacus - has four "earth" beads below the "reckoning bar" (these are the "ones") and one "heavenly" bead above (the "fives"). Moving a bead towards the bar turns it "on", allowing each rod to represent a number from 0-9. The numbers of rods varies from 13 and 17 to 23 or even 27 (longer soroban enable more complicated calculations incorporating several different numbers at the same time). Below is a video of my wife, who was trained to use the soroban in a bank to confirm the day's transactions, adding the numbers from 1 to 10 (totaling 55) and then adding two 4-digit numbers. If you want to try it out yourself, no need to buy one: there are loads of drill books as well as various apps which allow you to practice on a phone or tablet (check out soroboard=そろボード in Japanese and Soroban Training in English - there is also a wonderful video of kids using sorotouch=そろタッチ here). A great way to keep the brain active - let me know what you think in the COMMENTS!


James Burgess said...

That has got to be my favourite blog. Those youngsters are just so impressive and I say that as someone with a maths degree. I simply couldn't read those numbers that fast, let alone add them up. How do they do it? The statistic that surprised me was that UK are 11th in the PISA rankings as, in my experience, so many of my fellow Brits are numerically illiterate!

Chris Burgess said...

Glad you liked the post. Took a bit of work figuring out how to use the soroban for this math illiterate Brit!