 In Chungyong kangŭibo (中庸講義補) [Supplement to Lectures on the Doctrine of the Mean], Tasan (Kugyŏk yŏyudang chŏnsŏ: vol. 1: 390) queries the link between the “Diagram of the Supreme Ultimate” (which had provided the foundation for T’oegye’s onto-cosmology) and original Confucian ideas, noting that, “it was written over a thousand years after Confucius”, hence not found in “original” Confucianism at all. In another text, Maengja yoŭi (孟子要義) [The Essentials of The Mencius] Tasan notes that