|Table of contents||Table of diagrams
Not achieving the aim to make life
Achieving aim but inefficient
Efficiency describes the relative effectiveness of a move, sequence of moves or a set of stones in relation to what a player hopes to achieve vis-à-vis corresponding stones on the board. A player plays efficiently by using the fewest plays necessary to accomplish their task, or aim.  Players who exhibit greater efficiency in surrounding and controlling territory over the course of a game will have a greater chance of winning. Efficiency can be about territory, influence or other aspects.
achieves the aim of making life, but could do so more efficiently. (Later, White can reduce the territory with a-b to 2 points)
makes life and 4 points, 2 better than the previous diagram. is the most efficient way to make life in this position.
As always, one must consider the Global situation when choosing a move to play. While one may find an efficient Local sequence to play, that does not mean that is the most urgent move to play yet on the whole board. For instance, making a 2 point life for a small group of stones may be inferior to attacking a large dragon on the rest of the board.
- Stones are said to perform work.
- Efficiency is one of the aspects of shape.
- Examples of efficient moves can be found at double-purpose plays.
- Overconcentration is a typical kind of inefficiency
 RobertJasiek: A player can often achieve different degrees of efficiency with the same number of his related plays. Among different variations with the same number, he can choose the variation with the best achieved efficiency. See also RobertJasiek/Efficiency.