The modern Japanese philosopher WATSUJI Tetsuro (1889-1960) is known for his theory of "ningen 人間." As stated by Watsuji, the Japanese word "ningen 人間" (human being), which is derived from Chinese, originally meant "人與人之間" (between people), "(人)世間" (world). And ''ku 空'' (emptiness), the supreme principle of Watsuji's ethics, is the practical law of "ningen" existence. This paper clarifies the ideological background of Watsuji, and demonstrates how his so-called emptiness is inspired by ''dharma'' in Original Buddhism.
