The head is large, angular, broad, and rather short. It is trapezium shaped when viewed from above and in front. Eyes - Oval and set wide apart. The space between the eyes is equal to about twice the length of the eye (eye opening). Frank expression. The haw should not be visible. Color-hazel to dark brown for a dog with a black mask, lighter color tolerated but not sought after in dogs with either a brown mask or without a mask. Fault-Protruding eyes. Ears - The ear is small in proportion to the skull and of a slightly darker color than the coat. The front of the ears’ base is slightly raised. They should fall back, but not hang limply. The front edge of the ear is close to the cheek when the dog is attentive. The tip is slightly rounded, and should not reach beyond the eye. Set rather high, at the level of the upper line of the skull, thus emphasizing the skull width even more. Skull - Back Skull in the male: The perimeter of the skull measured at the point of its greatest width corresponds roughly to the height at the withers. In bitches it may be slightly less. Its volume and shape are the result of the spacing of the lower jaw bones, and the very well developed temporal area, upper-orbital area, and zygomatic arches. The cheeks are prominent due to the very strong development of the muscles. The skull is slightly rounded from one side to the other. The frontal groove is deep. The forehead, characterized by well developed eyebrows, dominates the face. However the skull is still wider than high. The head is furrowed with symmetrical wrinkles on each side of the median groove. These deep ropes of wrinkle are mobile depending on whether the dog is attentive or not. Stop - The stop is very pronounced, almost forming a right angle with the muzzle (95 to 100 degrees). Fault - Extreme characteristics such as a very short muzzle, flat skull and a swollen fold behind the nose. Muzzle - Powerful, broad, thick, and rather short. Should not be fleshy below the eyes. When viewed in profile, the foreface is very slightly concave with moderately obvious folds. Its width decreases only slightly from the root of the muzzle to the tip. When viewed from above it has the general shape of a square. When viewed from the side, the top lines of the skull and muzzle form an angle that converges at, or near the end of the muzzle. When the head is held horizontally, the end of the muzzle, which is truncated, thick and broad at the base, is in front of a vertical tangent to the front of the nose (The nose is slightly set back from the front of the muzzle.). Its perimeter is almost two thirds of that of the head. Its length varies between one third and one quarter of the total length of the head, measured from the nose to the occipital crest. The ideal length of the muzzle is between these two extremes. Nose - Broad, with well opened nostrils. Self colored according to the color of the mask. Slightly upturned permissible. Upper lip - Thick, moderately pendulous yet retractile. When viewed in profile it shows a rounded lower line and covers the lower jaw on the sides. When viewed from the front, the edge of the upper lip is in contact with the lower lip, and drops on either side thus forming an inverse, wide V. Jaws - Very powerful, and broad. Undershot so that there is no contact between the upper and lower incisors. The lower jaw curves upwards. The chin is very pronounced and should neither overlap the upper lip exaggeratedly nor be covered by it. Disqualification - Mouth not undershot; wry jaw. Bite - Undershot. Fault - Incisors constantly visible when the mouth is closed. Severe Fault - Canines constantly visible when the mouth is closed. Teeth - Strong, particularly the canines. Lower, canines set wide apart and slightly curved. Incisors well aligned especially in the lower jaw where they form a straight line. Severe Fault - Long narrow head with insufficiently pronounced stop, with a muzzle measuring more than a third of the total length of the head (lack of type in head).