Great page (in Japanese) on how to wear kanzashi. Yes, there are rules.
Usagi kanzashi ~ Year of the Rabbit
日本髪::::how to adorn traditional Japanese hair part2 The Kanoko : bending and tying in , you can decorate the back shot . 5. Before comb - flat casting set : I am plugged into the roots of bangs and topknot . 6. Ball hairpin : You inserted horizontally to flat out hairpin and symmetry .