The main character describes his problem/dilemma in this book as being sort of stuck in a cave, a "personal matter" that is purely his own and that he can't really share with others. Reading this book is being stuck in that cave with Bird, meaning that it's dark and impossible to see a way out.

The ending actually reveals Oe's struggle to figure a way out for the character and the novel - the deus ex machina is not very fulfilling but also sort of understandable given how the narrative progresses.