Poets who belonged to the Ningyo Shi Sha (Mermaid Poetry Publishing House) played a vital role in the development of free verse style of modern poetry. What the various poets shared was religious subjects. Religious elements in the poetry of Bocho Yamamura and Sakutaro Hagiwara used to be interpreted in the context of Christianity, especially because Yamamura was a missionary of the Episcopal Church. However Buddist influences on their poetical works should not be overlooked. Comparison of the images of "fish", "sin" and "regret" in their works with the ones in the Bible and the Buddist Scriptures will prove the point I propose.