I Don't Hear Any Of Them Whining About So-called Math Anxiety

This is as impressive as it is intimidating:

And the high point of the championship is the category called "Flash Anzan" – which does not require an abacus at all.

Or rather, it requires contestants to use the mental image of an abacus. Since when you get very good at the abacus it is possible to calculate simply by imagining one.

In Flash Anzan, 15 numbers are flashed consecutively on a giant screen. Each number is between 100 and 999. The challenge is to add them up.

Simple, right? Except the numbers are flashed so fast you can barely read them...

Flash Anzan was invented a few years ago by an abacus teacher, Yoji Miyamoto, who wanted to design a maths game that was only solvable by calculation with an imaginary abacus, a skill known as anzan.

When the contestant sees the first number he or she instantly visualizes the number on the imaginary abacus. When they see the second number they instantly add it to the number already visualized, and so on. At the end of the game the contestants cannot remember any of the numbers, or the intermediate sums. They only retain the final answer on the imaginary abacus.

Performing arithmetic using an imaginary abacus is the fastest way to perform mental calculations. Earlier this year the Japanese Naofumi Ogasawara won the Mental Calculation World Cup using the technique. The previous winner, Priyashi Somani, from India, did too.

There's more, including video, at the link.