GENERAL APPEARANCE:
The mastiff is a large, massive, symmetrical dog with a well-knit frame. The impression is one of grandeur and dignity. Dogs are more massive throughout. The Bitches should not be faulted for being somewhat smaller in all dimensions while maintaining a proportionally powerful structure. A good evaluation considers positive qualities of type and soundness with equal weight.
SIZE, PROPORTION, SUBSTANCE:
Size - Dogs, minimum, 30 inches at the shoulder. Bitches, minimum 27.5 inches at the shoulder.
Fault - dogs or bitches below standard. The further below standard, the greater the fault.
Proportion - Rectangular, the length of the dog from the fore chest to rump is somewhat longer than the height at the withers. The height of the dog should come from depth of body rather than from the length of leg.
Substance - Massive, heavy boned, with a powerful muscle structure. Great depth and breadth desirable.
Fault - Lack of substance or slab-sided.
HEAD:
In general outline giving a massive appearance when viewed from any angle. Breadth greatly desired.
Eyes - Set wide apart, medium in size, never too prominent.
Expression - Alert but kindly. Colour of eyes brown, the darker the better, and showing no haw. Light eyes or predatory expression undesirable.
Ears - Small in proportion to the skull, V-shaped, rounded at the tips. Leather moderately thin, set widely apart at the highest points on the sides of the skull continuing the outline cross the summit. They should lie close to the cheeks when in repose. Ears dark in colour, the blacker the better, conforming to the colour of the muzzle.
Skull - Broad and somewhat flattened between the ears, forehead slightly curved, showing marked wrinkles that are particularly distinctive when at attention. Brows (superciliary ridges) moderately raised. Muscles of the temples well developed, those of the cheeks extremely powerful. Arch across the skull a flattened curve with a furrow up the centre of the forehead. This extends from between the eyes to halfway up the skull. The stop between the eyes well marked but not too abrupt. Muzzle should be half the length of the skull, thus dividing the head into three parts, one for the foreface and two for the skull. In other words, the distance from the tip of the nose to the stop is equal to one-half the distance between the stop and the occiput. Circumference of the muzzle (measured midway between the eyes and the nose) to that of the head (measured before the ears) is as 3 is to 5.
Muzzle - Short, broad under the eyes and running nearly equal in width to the end of the nose. Truncated, i.e. blunt and cut off square, thus forming a right angle with the upper line of the face. Of great depth from the point of the nose to the underjaw. Underjaw broad to the end and slightly rounded. Muzzle dark in colour, the blacker the better.
Fault - Snippiness of the muzzle.
Nose - Broad and always dark in colour, the blacker the better, with spread flat nostrils (not pointed or turned up) in profile.
Lips - diverging at obtuse angles with the septum and sufficiently pendulous so as to show a modified square profile.
Canine Teeth - Healthy and wide apart. Jaws powerful. Scissors bite preferred, but a moderately undershot jaw should not be faulted providing the teeth are not visible when the mouth is closed.
NECK, TOPLINE, BODY:
Neck - Powerful, very muscular, slightly arched and of medium length. The neck gradually increases in circumference as it approaches the shoulder. Neck moderately 'dry' (not showing an excess of loose skin).
Topline - In profile the topline should be straight, level, firm, and not swaybacked, roached, or dropping off sharply behind the high point of the rump.
Chest - wide, deep, rounded and well let down between the forelegs, extending at least to the elbow. Forechest should be deep and well defined, with the breastbone extending in front of the foremost part of the shoulder. Ribs well rounded. False ribs deep and well set back.
Underline - There should be reasonable, but not exaggerated, tuck up.
Back - Muscular, powerful, and straight. When viewed from the rear, there should be a slight rounding over the rump.
Loins - Wide and muscular.
Tail - Set on moderately high and reaching to the hocks or a little below. Wide at the root, tapering to the end, hanging straight in repose, forming a slight curve, but never over the back when the dog is in motion.
FOREQUARTERS:
Shoulders - Moderately sloping, powerful and muscular, with no tendency towards looseness. Degree of front angulation to match correct rear angulation. Legs straight, strong and set well apart, heavy boned.
Elbows - Parallel to body.
Pasterns - Strong and bent only slightly.
Feet - Large, round, and compact with well arched toes. Black nails preferred.
HINDQUARTERS:
Hindquarters - Broad, wide and muscular.
Second Thighs - Well developed, leading to a strong hock joint.