Thread:Lord Hyōga/@comment-5126314-20140616200939/@comment-4576906-20140617011807

Yes; the anime more or less says it was ten years in several instances, whereas the manga, perhaps, is a little more ambiguous. At the very least, I don't think we can say it was 15 years. I don't read the manga as often as I would like, so I can't say for sure whether anyone says 15, but I can't recall any source that says that. Assuming there isn't, if there's any uncertainty as to when, for the sake of simplicity, we can round it to a decade/10 years, so long as we don't say "exactly ten years," though I can't think of why any of the articles would need to be worded so precisely, so that shouldn't be too much of an issue.