In addition to the comment posted by the iaido-ka, those studying kobudo often don't start training with bladed weapons until 1st dan. Kamas are an excellent example (the little scythe-like weapon). When the student is ready they're given a set of wooden ones, and here's one of the reasons: When perferming or practicing a few of the techniques, the blade ends up on the opposite side of your back. If you're not careful, you end up removing your own kidney.
Success cannot be attained except by piling effort upon effort.