Inbreeding concentrates both good features and faults, strengthening dominants and bringing recessives out so they can be evaluated. It supplies the breeder with the only control that can be had over prepotency and homozygosity. The closest breeding of all, is brother to sister. The most important phases of inbreeding being to choose as nearly faultless partners as possible and to cull or select rigidly from the resultant progeny.

This bitch Cita v Da Rie Mar Hill, the result of breeding SGR 1937/8GV CH (US) Pfeffer von Bern to his sister 1937 GVX CH (US) Perchta v Bern, was the granddam of GV CH (US&CAN) Valiant of Draham, Owned by David I. McCahill.

Source: This is the German Shepherd Dog by Captain William Golbecker & Ernest H. Hart, pages 53/54