The word "blank space" means that in the artistic creation of calligraphy and painting, in order to make the picture and composition of the whole work more harmonious and exquisite, the corresponding blank space is deliberately set aside to give people room for imagination. Dry pen refers to the dry pen that appears when the ink in the pen is about to run out. The dry pen is mostly cursive, and the pen is dipped in ink at a time, from the ink head to the ink tail.