Although initially fraught with tension, spanning roughly two decades, Buddhists employed various strategies to combat the spread of Christianity and uphold their traditional values. As the 1890s dawned, a new wave of Buddhists emerged, spearheading the reconstruction of Japanese Buddhism through processes of secularization and westernization in alignment with the currents of the Meiji Restoration. This paper delves into the intricate relationship between Buddhism and Christianity in Japan following the Perry Expedition. By scrutinizing the writings and orations of numerous Buddhist leaders spanning the period from the 1860s to the 1890s, this paper elucidates the multifaceted conflicts and interactions between Japanese Buddhism and Christianity. A nuanced analysis of their endeavors, reveals the evolving dynamics and strategies employed by both religions in navigating their coexistence in Japan's religious landscape, where both involuntarily made corresponding relative changes to be involved in social trends and Japanese traditions. This paper also discusses the cooperation and potential union between the two religions at the beginning of the 19th century, when New Buddhists received education in Western philosophy and examined Christianity. In short, the Buddhist-Christian relationship underwent a conversion from opponents to equal religion, even collaboratively enforcing social justice and care.