The splash of a frog, a cricket chirping from beneath an empty samurai helmet, “the cool fragrance of snow”: Such closely observed moments in nature, often marrying unlikely elements, distinguish Basho’s poetry. Haiku (a three-line verse) originated as the first verse of longer poems. Using plain language in the service of spiritual insight, Basho raised the form to literature, each poem like a polished stone that, when dropped in water, creates an infinity of ripples.