Guǐ gǔ zǐ 鬼谷子 (“Master of the Ghost-Valley”) — legendary Warring-States figure, traditionally the teacher of the diplomats Sū Qín 蘇秦 and Zhāng Yí 張儀 and of the military thinker Sūn Bìn 孫臏. The figure is shadowy and probably composite; the eponymous text KR5d0048 Guǐ gǔ zǐ 鬼谷子 is a Warring-States / Hàn rhetorical-diplomatic treatise on persuasion and political strategy.