I don't know if this is really taught in japanese schools, but it's pretty cool.

[youtube]http://www.youtube.com/watch?v=e-P5RGdjICo[/youtube]

7 years in Japan and never seen this.
My Japanese partner has a lifetime in Japan, and never seen it either.
Doesn't mean it's not taught there though.

Interesting to someone like me who doesn't grasp math all that well.

Is it writing down what an abacus does?

Nice algorithm, but I think that it's slower than the conventional one for a number of digits >2 or for high digits, as in 7989x968.