"tatami" has been changing together with people's life style. "tatami" became common for people in the middle of the edo era. farmers started to use them in the meiji era. the removal of "tatami" regulation made them more common in the meiji era. japanese people often dry the "tatami". if the "tatami"'s surface was discolored, people often turned them over. with the economic growth after world war two people started to use chairs and carpets. japanese people think flooring is not relaxing or soundproof enough, so people still use "tatami" now.