Rather than the generic ‘algae’ the poem refers specifically to miru, or ‘thick-haired codium’ as it is in English, which grows in deep pools along rocky coasts. The individual filaments, which can be as long as 30 centimetres, often grow together to form a velvety mat.
There was a belief in Old Japan that grass, folded up and used as a pillow, had the power to ward off misfortune. As travelling was one of the most dangerous activities people could undertake, it was often done on a journey and so kusa makura ‘grass pillow’ became a pillow-word for ‘journey’.
Sanuki lay in the modern island of Shikoku which, the Kojiki relates, is a deity with four faces. It is towards one of these faces that Hitomaro and his companions are heading when their vessel is struck by the storm.
The woman in question was an uneme, a beautiful woman brought from the provinces to serve at court. The poems hint obliquely that she may have killed herself, and the fact that she left a husband, and uneme were forbidden to marry suggests a reason.
Nakisawa Shrine lies in present day Nara Prefecture in Ki no Moto in Sakurai City. It is dedicated to the goddess Nakisawame (Weeping Marsh Woman) who sprang from the tears shed by the god Izanagi (creator of Japan) on the death of his wife, Izanami.