The video above was posted at Neatorama several weeks ago. Today I found some explanatory text at Wikipedia:
The abacus system of mental calculation is a system where users mentally visualize an abacus to do calculations. No physical abacus is used; only the answers are written down. Calculations can be made at great speed in this way. For example, in the Flash Anzan event at the All Japan Soroban Championship, champion Takeo Sasano was able to add fifteen three-digit numbers in just 1.7 seconds.The technique demonstrated in the video seems to be quite different from the "finger math" using a mental abacus for counting.
This system is being propagated in China, Singapore, South Korea, Thailand, Malaysia, Japan and India. Mental calculation is said to improve mental capability, increases speed of response, memory power, and concentration power.
Many veteran and prolific abacus users in China, Japan, South Korea, and others who use the abacus daily, naturally tend to not use the abacus anymore but perform calculations by visualizing the abacus. This was verified when the right brain measured heightened EEG activity when calculating and compared with non-veterans who were using the abacus to perform calculations.