The empty triangle — bad shape
Go rates small arrangements of stones — shapes — by efficiency: the same stones, placed better, produce more liberties, more eyes and more ground. The most famous bad shape is the empty triangle: three stones around a useless point, one stone's effort wasted and liberties short. Its cousins are good: the bamboo joint, the tiger's mouth, the clean one-space jump — learn a handful and your moves start to look right on their own. The test in front of you is liberties: extending in a straight line keeps the three-stone group breathing freely, while the bent extension creates an empty triangle and pays one liberty for nothing. Before bending, always ask what the third stone buys. Black to play: extend for the most liberties.