How does the Japanese multiplication work?

Counting sticks and stones

The Japanese multiplication method makes everybody feel "I wish they taught math like this in school."

It's not just a cute visual tool: it illuminates how and why long multiplication works.

Here is the full story.

First, the Japanese multiplication method.

The first operand (21 in our case) is represented by two groups of lines: two lines in the first (1st digit), and one in the second (2nd digit).

One group for each digit.