Takeo Sasano (Japan) correctly added 15 sets of three-digit numbers flashed on the screen in 1.83 seconds at All Japan Soroban Championships in Yasu-shi, Shiga-ken, Japan, on 8 August 2010.

The time begins when the first three-digit number is flashed on the screen and ends when the last number is flashed. The skill is in memorising these numbers then adding them. The competitor has then 5 seconds to write the answer. At Mr Sasano’s attempt, 15 numbers were flashed up in just 1.83 seconds – practically a blur.
http://www.youtube.com/watch?v=p_Terdik7aA