In 1987, motivated by anxiety over his inability to produce a followup novel to his earlier sucesses, Ishiguru made a deal with his wife Lorna: he would write every day from 9h-2230h, with brief meal-breaks, 6 days a week: four weeks later, he finished Remains of the Day. [link]
Ishiguru admits it took much longer to tidy the book up, the first month, however, is when the major creative breakthroughs occurred. The story is presented at greater length in his piece in The Guardian.
As impressive as a one month novel is, it turns out that a major novel has been written in just 9 days … after a year of thinking about it
Jim Harrison, author of Legends of the Fall … thinks about his characters, without writing a word, for long periods of time. Then, when he’s ready to write, he doesn’t look back. “I wrote Legends of the Fall in nine days,” he said, “and when I re-read it, I only had to change one word. There was no revision process. None. I had thought so much about the character that writing the book was like taking dictation.” [link]