Japanese knot tying meaning and culture

I have a pretty far fetched question. In the game Nioh 2, I noticed so many different knots and folded origami on the tori gates and on samurai armor. One being on the Taira no Kageyaki armor or the bow knot. I know the folded paper wards off spirits. But the knots I have no idea about. They're beautiful. I know they have symbolism but have no idea where to start to learn.

by BurnOne1