陳皡 Chʽên Hao appears to have been a contemporary of Tu Mu . Chʽao Kung-wu says that he was impelled to write a new commentary on Sun Tzǔ because Tsʽao Kung’s on the one hand was too obscure and subtle, and that of Tu Mu on the other too long-winded and diffuse. 105 Ou-yang Hsiu , writing in the middle of the 11th century, calls Tsʽao Kung , Tu Mu and Chʽên Hao the three chief commentators on Sun Tzǔ (