NMC Standard for the Rumpwhite
Any standard colour but having a white rump. The line of demarcation should be straight and encircle the body so that the lower third of the mouse, including the hind feet and tail is completely white. The remaining colour must be without any white markings at all and should conform with the standard laid down for that variety. Rump White Tan to be shown in Rump white class.
Originator: R Meredith 1969