“The Sea Darkens” belongs to a period of Bash’s career in which he was searching for his unique identity as a poet. Most critics agree that he reached at this stage a peak level in the composition of haiku. To see how the poem distributes the seventeen syllables among the lines in a 5-5-7 (irregular) pattern, it is necessary to look at the Japanese words:
5Umi kurete The sea darkens5Kamo no koe The cries of the wild ducks7Homokani shiroshi Are faintly white.
Bash wrote this haiku on the first of his four long journeys. The poem, written on a day spent on the seacoast, appeared in a travel journal of that trip, Nozarashi kik (1687; The Records of a Weather-Exposed Skeleton, 1966), in 1687.
Bash uses synesthesia as a significant convention in this poem. Synesthesia refers to one sense being described in terms of another. Thus, the sound of the duck is described as being a color, white. The cosmic loneliness, or stillness, amid the approaching darkness is broken by the sounds of the ducks flying overhead and is interpreted as “seeing white,” so to speak, rather than as “hearing sound.” Thus, a vision of the ultimate interrelatedness of all things and events in the universe is captured in this tiny poem.