Beauty of Tatami – hygroscopic character and a characteristic to discharge the humidity

Tatami has hygroscopic character, one piece of tatami can absorb about 500cc water which is about the same capacity of a plastic bottle.

It absorbs atmospheric moisture in the humid rainy season and relax unpleasantness somewhat.

A notable mark of a tatami is that it also has a characteristic to discharge the humidity.
It discharges the water when air dries and, as a result, the humidity of a room is kept.
It depends on the time of the year and a place, but humidity 40% is called an aim. The rush grass which is materials of a tatami seems to totally breathe.

However, moisture absorption power weakens as the tatami gets old.
It is recommended sometimes expose it to fresh air to revive it.

Now, do you see how it fits with Japanese living as a flooring material where in summer it has high humidity and in winter it’s dry.