Affinities of certain bloodlines to work best when mated to other specific bloodlines. Nicks were first noted at stud farms where daughters of one stallion standing there were successfully bred to another of the farm’s stallions. Prominent nicks include *Princequillo x *Nasrullah; Northern Dancer x Buckpasser; *Bull Lea x *Blenheim II. There are also “negative” nicks as noted by Buckpasser x Bold Ruler.