Board Thread:Naruto Discussions/@comment-32554648-20180706173543/@comment-3279282-20180718070507

FlatZone wrote: @seelentau, they only care if it fits into the main story as in part of the main story.. if not they call it a side story. I never once saw the light novels or the Shindens be called Side Stories so according to this logic they are what we would call canon.

Then Kakashi Gaiden wouldn't be canon lol

It's as I said: Canon is a Western invention, it doesn't exist in Japan or at least has little to no importance.