Unbleached horsehair is important because bleaching the horsehair weakens and damages it. However, this isn't something you should worry about - picking the horsehair is done by your luthier, as he will have better quality material available to him. Hopefully this guide helped you on your journey to finding a new bow! As a closing note, remember that just because a bow works for 100 people, it doesn’t mean that it has to work for you too, everyone is different. Finally, congratulate yourself! With new equipment, you will proceed further on your journey of violin playing and satisfaction.