What is いあいどう?

Iaido (居合道　いあいどう) is a Japanese traditional martial art. Different from kendo (剣道　けんどう), another famous martial art, iaido emphasizes being aware and capable of quickly drawing the sword and responding to sudden attacks. [1] This leads to several special features of iaido, making it pretty special.

Iaido is suitable for both men and women.

For example, it does not needs opponents or companions to practice iaido. People may imagine opponents while exercising iaido.

Besides, focusing on "sudden", iaido is sort of different from regular "martial arts". Instead of mere strength, iaido requires more about the mind and reaction.

Here is a link to a set of videos that demonstrate iaido with English explanations. (Note: the link leads to a Chinese website.)

Reference:

[1] Iaido - Wikipedia. https://en.wikipedia.org/wiki/Iaido.