An opening rein merely opens out to the side, never back, and is used to guide the horse while the leading rein turns either a very green horse or very balky horse.

• 而开缰几乎不把缰牵引到马体侧，更不能到马的后部，用于引导马，与之对应，引导缰则用于未训练成的马或性格倔强的马。