Nobuyuki Yuasa notes that Bashō studied Zen meditation under the guidance of the Priest Buccho, though it is uncertain whether Bashō ever attained enlightenment.The Japanese Zen scholar D. T. Suzuki has described Bashō's philosophy in writing poetry as one requiring that both "subject and object were entirely annihilated" in meditative experience. Yuasa likewise writes: "Bashō had been casting away his earthly attachments, one by one, in the years preceding the journey, and now he had nothing else to cast away but his own self which was in him as well as around him. He had to cast this self away, for otherwise he was not able to restore his true identity (what he calls the 'everlasting self which is poetry'"). Yuasa notes "The Narrow Road to the Deep North is Bashō's study in eternity, and in so far as he has succeeded in this attempt, it is also a monument he has set up against the flow of time."