Nishida discussed the problem of love in his two philosophico-religious works, “A study of Good”(1911)and “Self-conscious Realization of Nothingness”(1932). At first Nishida considered the essence of religion as “Unity of Human with God”, and love as a “Unifying Act” in “A Study of Good”. His concept of religion seems, however, to have been radically changed and deepened in “Self-conscious Realization of Nothingness”: the essence of religion is not to be seen as an immediate unity of Human with God, but as the retrieved oneness mediated through God’s “Agape”, i.e. His self-emptying love. In this paper, I will explain why such a radical sift has happened. To this purpose, I would like to focus on Nishida’s idea of “Reality” and “the historical world” as a new theme of his later philosophy, heralding a new dimension of dialogue between Nishida’s philosophy and Christianity.