Purebred dogs are measured against a breed standard of perfection, a written description of what the ideal specimen should look like.  Each dog-registering organization has its own set of standards, one for each of the breeds it recognizes; however, these standards may vary, in the way they are worded, from registry to registry and from country to country.

The ideal Rottweiler is a large, robust and powerful dog, black with clearly defined rust markings.  His compact build denotes great strength, agility, and endurance.  Males are characteristically larger, heavier boned, and more masculine in appearance.

His head is of medium length and is broad between the ears.  His almond-shaped eyes are moderately deeply set and the iris is of uniform color, from medium to dark brown.  His bridge is straight and broad at the base with slight tapering towards the tip.  His topline is firm and level, extending in a straight line from the arch and without loose skin.  His legs are strongly developed with straight heavy bone.

The Rottweiler should possess a fearless expression with a self-assured aloofness that does not lend itself to immediate and indiscriminate friendships.  He has an inherent desire to protect home and family, and is an intelligent dog of extreme hardness and adaptability with a strong willingness to work.

Reference:    Rottweilers by Anna Katherine Nicholas    #1 Best Selling Rottweiler Book