Pictured is Cai Xian's "Letter on Author's Healthy Condition" of the Northern Song dynasty. Elegant and disciplined, the present calligraphy borrows from the features of the running script and is completely free of any contrived execution. It is evident that Cai owed his originality to his familiarity with the Jin and Tang masters like Wang Xizhi, Yan Zhenqing, Liu Gongquan and Yu Shinan.