Chinese characters are written from right to left, top to bottom. As the authors of old wrote or painted with brush pens, the ink dried slowly, so they used the armrest to prevent their arms and hands from touching the wet paper.
中國文字的書寫方式，由右而左，由上而下，古時文人以毛筆寫字、畫畫，墨跡乾得慢，他們就在手臂下墊個臂擱，以免觸碰到紙。