In the book the rules are a bit fuzzy. It's told in first person so it isn't really explained so much as related to the reader from a character who is also conf

In the book the rules are a bit fuzzy. It's told in first person so it isn't really explained so much as related to the reader from a character who is also confused about how the time loop works. Although who knows, maybe there's some grand explanation in the books that haven't been translated yet. It's a good read, I can't really predict where the author will go with this after Book IV.