Examination analysis: according to the knowledge learned, the font in the picture is cursive, and Yan Zhenqing and Liu Gongquan are regular script calligraphers; According to the description in the materials, it can be identified as Huai Su's work. Therefore, B. Wang Xizhi is good at cursive script, and his calligraphy features are as follows:
Delicate brushwork, elegant and clever brushwork, euphemistic and implicit brushwork, like flowing water, beautiful structure, delicate bones and delicate stippling.