In the game of Go (Wei Qi/Badouk), a "dog's head" is the shape formed by the following arrangement of stones:

.....
.o...
..aob
.o...
.....

(No stones at a or b, but see below)

It is considered to be a good shape to make, but perhaps overconcentrated, if there aren't many opposing stones in the vicinity. It is flexible, since any of the three stones can be sacrificed, without destroying the group as a whole, but at the same time is impossible to cut apart without a very complicated fight that will vastly favor the defender.

Note that playing the rightmost stone at the point "a" would make a tiger's mouth instead, while a play at "b" is what is known as the horse's head. Experts often say that the horse's head is generally better than the dog's head, but of course, different situations call for different moves. Certainly, the horse's head is better if the group is already relatively safe, or the intention is to jump into the centre of the goban (Go board), but the tighter play of a dog's head might be necessary if the stones are under fierce attack, or the opponent has stones nearby in a good place to cut the horse's head.