行书, or "Xing Shu," is a style of Chinese calligraphy that combines elements of both regular script and cursive script. It is known for its fluidity and expressiveness, allowing for a balance between legibility and artistic flair. This style is often used for personal letters and informal documents, making it popular among calligraphers. The development of 行书 can be traced back to the Han Dynasty, where it evolved to facilitate faster writing. Notable calligraphers, such as Wang Xizhi, are celebrated for their mastery of this style, which remains influential in contemporary Chinese calligraphy.