Watsuji Tetsuro's idea of aidagara (often translated as 'betweenness') is an essential concept in his ningen rinrigaku with a robust Confucian heritage. As he begins his reflection on aidagara from Mencius' concept of gorin or 'five relationships' it seems that Watsuji tries to reinterpret gorin. However, unlike Yangmingism and the twentieth-century Chinese New Confucianism, Watsuji does not emphasise individual subjectivity. Instead, in both Rinrigaku and Fudo, Watsuji reduces individual self into aidagara and aidagara into the Buddhist notion of Ku. In light of Mou Zongsan's moral metaphysics, this paper argues that Watsuji's ningen rinrigaku fails to provide a consistent interpretation of Mencius' teaching of gorin. According to Mou, an individual's subjectivity whose mind nature is granted by Heaven preceds and producs mutual relationships among human beings. However, such idea of Heaven is omitted in Watsuji's anti-Neo-Confucian understanding of Mencius. Instead, Watsuji argues that the individual's moral consciousness arises from aidagara, which is the negations of self and others. In fact, his notion of self-negation contradicts with Mencius 7A. However, instead of accusing Watsuji of misunderstanding Mencius, this paper suggests one may understand Watsuji's ningen rinrigaku as non-Confucian ethics instead of a consistent interpretation of Mencius.