at/* B/* C/* d/d P/*, or
at/* B/* C/* D/* ln/ln P/*
"Eyes black. The colour should be a medium slate blue. The tan belly shall be a rich golden orange hue, as rich as possible and there should be a clear line of demarcation between top colour and tan running in a straight line along flanks, chest and jaws. There should be no brindling or guard hairs. Colour of feet should be inside tan, the remainder of foot the same as top colour. Wholly tan feet considered a greater fault than feet all same colour as top."
Breeding information below the pictures.
Blue tan is nothing like black or chocolate tans in color! The belly colour is never as deep as with these above-mentioned varieties, due to the blue being a dilute colour. This result with the tan being diluted into light buff. A good judge will recognize this difficulty and expect the best possible tan for a blue tan, not the richest possible tan as in other tans. However the top colour should be as good as in a self blue.
In order to get blue tan, breed blue to black tan and two of the resulting black tans together or with a blue. Continue working with blue tan. Being a color of recessive gene, crossing with black or Chocolate tan (do not use Chocolate tan if you aren't aiming for Lilac tans) will not produce blue tans in the first generation unless the outcross happens to carry d. With the "mock blue gene" leaden it is possible to get a much more fiery belly than with d/d.