Ink is not merely a medium in caoshu; it is an active participant in the calligraphic process, contributing to the dynamic energy and visual richness of each piece. This essay will explore the interplay of ink and brush, focusing on how calligraphers manipulate ink flow to create a range of textures, tonalities, and expressive effects. We will begin by exploring the role of ink consistency and density in caoshu, highlighting how the calligrapher uses both saturated and dry ink to achieve different effects. Variations in ink density are used to enhance the expressiveness of the script.