The kai and xing calligraphy types made quick progress in the Jin Dynasty and had a big influence on later calligraphers. Zhong You and Wang Xizhi were representative calligraphers of the time. Zhong You, a native of Changshe (present Changge County in Henan Province), was an officer of the Wei Dynasty (220-265). He was good at li and xing calligraphy, but was especially expert in kai calligraphy. A later Song Dynasty scholar called him the founder of kai calligraphy. Building on his inheritance of the li calligraphy of the Eastern Han Dynasty, Zhong formed his own natural and elegant calligraphy style. His typical works include Hejie Biao, Xuanshi Biao, Liming Biao and Huanshi Tie.

Wang Xizhi was a native of Linyi, Shandong Province. He had served as a general and an imperial officer in the Jin Dynasty. He learned much from the work of previous calligraphers, including the kai calligraphy of Zhong You, the cao calligraphy of Zhang Zhi and that of Li Si and Cai Yong. Some people have described his calligraphy as "the dragon jumping over the heavenly gate and the tiger lying in the watchtower of the phoenix." Wang's calligraphy has a quiet beauty. Compared with Zhong You's handwriting, Wang's calligraphy is less influenced by li calligraphy. He wrote with more fluidity and grandeur. His style survives to the present, and so he is known as the Calligraphy Sage. Original examples of Wang Xizhi's handwriting are rarely seen today. Most of the works we can see now are rubbing copies of his works by later people. Wang Xizhi was good at writing many calligraphy types but the xing style Lan Ting Xu (Preface to the Literary Gathering at the Orchid Pavilion) is the most representative of his works.

The story behind this work is that in 353, Wang Xizhi invited 41 guests to join him at the Orchid Pavilion by a small, meandering stream for the purification rites of spring. Each guest was asked to compose a poem. The poems were collected, and Wang himself wrote the Preface to the Orchid Pavilion Collection in his trademark calligraphic style, a 324-character text in 28 lines. It records the happy gathering of the intellectuals, and shows that Wang had brought his calligraphy ability into full play during the gathering. The Song Dynasty scholar Mi Fu called Preface to the Orchid Pavilion Collection the world's best work in xing calligraphy. It is said that Emperor Taizong of the Tang Dynasty (618-907) treasured the work and had it buried in his tomb. so what we see now are only rubbings by others of this magnificent work.