The title is a Japanese phrase (kusamakura) which means sleeping outside. It occurs in the poem used as the epigraph for Across the Nightingale Floor:

The deer that weds
The autumn bush clover
They say
Sires a single fawn
And this fawn of mine
This lone boy
Sets off on a journey
Grass for his pillow

Shigeru also uses the phrase in the first chapter of Across the Nightingale Floor when he and Takeo spend the night on the edge of the Yaegahara plain, scene of the battle in which the Otori were defeated by the Tohan.

The title of each of the books in the Tales of the Otori is hidden within the text of the previous book. As a title, Grass for His Pillow holds, for me, suggestions of exile, suffering and separation, journeying, and an intense awareness of the physical world.

In Across the Nightingale Floor I established a world that draws on the powerful symbols of samurai and ninja, though I never mention these by name - I was hoping to avoid some of the cliches that have attached themselves to these figures. In Grass I wanted to look behind the symbols and see what their true effect might be on the society around them, particularly on women. In Across the Nightingale Floor the characters act heroically and there is "magic": in Grass the underside of heroism and magic are discovered - the treachery and self-serving of the warrior class, the cruelty and ruthlessness of the Tribe.

Cold and snow play an important role in the story; so does the landscape of the Three Countries.

On nights when wind mixing in the rain falls.
On nights when rain mixing in the snow falls.

One of the key themes of Grass is what is hidden and what is revealed. The books are full of secrets, which is why I don't really like talking about them or explaining too much. I hope my readers will discover the treasures that are hidden within for themselves.

Bound by the bargain he made with the Tribe, Takeo must join them and put his skills at their service. But their cruelty and injustice force him to try to escape. He is immediately sentenced to death by the Tribe and as winter draws in, he flees over the mountains to Terayama, helped by the outcaste, Jo-An.

Kaede, devastated by Takeo s leave-taking, returns to her parents home. She is pregnant with Takeo s child, but she and Shizuka decide to tell everyone that Kaede secretly married Shigeru and it is his child. She finds her house neglected and her estate almost ruined. Her mother is dead, her father is on the verge of insanity. Kaede is determined to educate herself and her sisters and save her domain. Then her father dies in mysterious circumstances: did he take his own life or was he murdered? She and her sisters face starvation in the coming winter, and Kaede enters into a pact with the strange, intriguing but sinister nobleman, Lord Fujiwara, in return for food and money.

When Kaede learns that Takeo is still alive and where he is, she journeys to see him. Reunited, they marry, but their union insults powerful forces around them, and takes them inexorably closer to war, death and terrible tragedy.