$$c This is a label for the diagram.
$$ ---------------------------------------
$$ | . . . . 1 1 1 1 1 1 1 1 1 1 1 . . . . |
$$ | . . . . 2 2 2 2 2 2 2 2 2 2 2 . . . . |
$$ | . . . . 3 3 3 3 3 3 3 3 3 3 3 . . . . |
$$ | . . . , 4 4 4 4 4 4 4 4 4 4 4 , . . . |
$$ | 1 2 3 4 . . . . . . . . . . . . . . . |
$$ | 1 2 3 4 . . . . . . . . . . . . . . . |
$$ | 1 2 3 4 . . . . . . . . . . . . . . . |
$$ | 1 2 3 4 . . . . . . . . . . . . . . . |
$$ | 1 2 3 4 . . . . . . . . . . . . . . . |
$$ | 1 2 3 4 . . . . . , . . . . . , . . . |
$$ | 1 2 3 4 . . . . . . . . . . . . . . . |
$$ | 1 2 3 4 . . . . . . . . . . . . . . . |
$$ | 1 2 3 4 . . . . . . . . . . . . . . . |
$$ | 1 2 3 4 . . . . . . . . . . . . . . . |
$$ | 1 2 3 4 . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------
- Click Here To Show Diagram Code
[go]$$c This is a label for the diagram.
$$ ---------------------------------------
$$ | . . . . 1 1 1 1 1 1 1 1 1 1 1 . . . . |
$$ | . . . . 2 2 2 2 2 2 2 2 2 2 2 . . . . |
$$ | . . . . 3 3 3 3 3 3 3 3 3 3 3 . . . . |
$$ | . . . , 4 4 4 4 4 4 4 4 4 4 4 , . . . |
$$ | 1 2 3 4 . . . . . . . . . . . . . . . |
$$ | 1 2 3 4 . . . . . . . . . . . . . . . |
$$ | 1 2 3 4 . . . . . . . . . . . . . . . |
$$ | 1 2 3 4 . . . . . . . . . . . . . . . |
$$ | 1 2 3 4 . . . . . . . . . . . . . . . |
$$ | 1 2 3 4 . . . . . , . . . . . , . . . |
$$ | 1 2 3 4 . . . . . . . . . . . . . . . |
$$ | 1 2 3 4 . . . . . . . . . . . . . . . |
$$ | 1 2 3 4 . . . . . . . . . . . . . . . |
$$ | 1 2 3 4 . . . . . . . . . . . . . . . |
$$ | 1 2 3 4 . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
I've labelled the first four lines here to make it easy to see what's so important about the corners. On most of the board, a fourth line move will threaten to make three points of territory relative to
one of the sides, but has no particular relation to the other sides - i.e., it's on the fourth line in one direction, and (say) the tenth line in the other direction. In the corner, however, a stone can be on the third line in relations to both sides, or the fourth line and the third line, and so on. This means that stones in the corner can be more efficient at making territory (they have points "under" them in two directions) and at living (more room for potential eyes).
Charts like this are pretty common:
$$c This is a label for the diagram.
$$ ---------------------------------------
$$ | . . . X . . . X . . . . X . . . . . . |
$$ | . . . X . . . . X X X X . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | X X X , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . X X . . . . . . . . |
$$ | . . . . . . . . X . . X . . . . . . . |
$$ | . . . . . . . . . X X . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . X X X . . . , . . . |
$$ | . . . . . . . . X . . . X . . . . . . |
$$ | . . . . . . . . X . . . X . . . . . . |
$$ | . . . . . . . . . X X X . . . . . . . |
$$ | X X X X X . . . . . . . . . . . . . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . , . X . . . , X X X X . , . . . |
$$ | . . . . . X . . . X . . . . X . . . . |
$$ | . . . . . X . . . X . . . . X . . . . |
$$ | . . . . . X . . . X . . . . X . . . . |
$$ ---------------------------------------
- Click Here To Show Diagram Code
[go]$$c This is a label for the diagram.
$$ ---------------------------------------
$$ | . . . X . . . X . . . . X . . . . . . |
$$ | . . . X . . . . X X X X . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | X X X , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . X X . . . . . . . . |
$$ | . . . . . . . . X . . X . . . . . . . |
$$ | . . . . . . . . . X X . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . X X X . . . , . . . |
$$ | . . . . . . . . X . . . X . . . . . . |
$$ | . . . . . . . . X . . . X . . . . . . |
$$ | . . . . . . . . . X X X . . . . . . . |
$$ | X X X X X . . . . . . . . . . . . . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . , . X . . . , X X X X . , . . . |
$$ | . . . . . X . . . X . . . . X . . . . |
$$ | . . . . . X . . . X . . . . X . . . . |
$$ | . . . . . X . . . X . . . . X . . . . |
$$ ---------------------------------------[/go]
Here you can see how much more efficient it is to use a certain number of stones to make territory in the corner, rather than on the sides or (heaven forbid!) in the center. Of course, you won't normally have the chance to sketch out a nice square territory like that. The start of it will look something like this, and then it will get fully fleshed out by fighting, invasions, endgame, and so on:
$$c This is a label for the diagram.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . X . . X . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . X . . X . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . X . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . X . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . X . , . . . |
$$ | . . . . X . . . . X . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------
- Click Here To Show Diagram Code
[go]$$c This is a label for the diagram.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . X . . X . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . X . . X . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . X . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . X . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . X . , . . . |
$$ | . . . . X . . . . X . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Now, everyone understands how to make territory, because at the end of the game all living groups have some territory, so the value of the corners for gobbling up points is easy to see. What is harder to appreciate, until you learn to attack your opponent and come under attack yourself, is how easy it is to live in the corner.
$$c This is a label for the diagram.
$$ ---------------------------------------
$$ | . X . . . X . X . X . . . . . . X X . |
$$ | X X . . . X X X X X . . . . . . X . X |
$$ | . X . . . . . . . . . . . . . . . X X |
$$ | X X . , . . . . . , . . . . . , . . . |
$$ | . . . . . . X X X . . . . . . . . . . |
$$ | . . . . . X . X . X . . . . . X X X X |
$$ | . . . . . X X X X X . . . . . X . X . |
$$ | . . . . . . . . . . . . . . . . X X X |
$$ | . . . . . . . . . . . . . X X . . . . |
$$ | . . . , . . . . . , . X X . X , . . . |
$$ | . . . . . . . . . . . X . X X . . . . |
$$ | . . . . . . . . . . . X X . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
- Click Here To Show Diagram Code
[go]$$c This is a label for the diagram.
$$ ---------------------------------------
$$ | . X . . . X . X . X . . . . . . X X . |
$$ | X X . . . X X X X X . . . . . . X . X |
$$ | . X . . . . . . . . . . . . . . . X X |
$$ | X X . , . . . . . , . . . . . , . . . |
$$ | . . . . . . X X X . . . . . . . . . . |
$$ | . . . . . X . X . X . . . . . X X X X |
$$ | . . . . . X X X X X . . . . . X . X . |
$$ | . . . . . . . . . . . . . . . . X X X |
$$ | . . . . . . . . . . . . . X X . . . . |
$$ | . . . , . . . . . , . X X . X , . . . |
$$ | . . . . . . . . . . . X . X X . . . . |
$$ | . . . . . . . . . . . X X . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]
When you commit yourself to living in the center rather than the corner, you're forced to devote nearly twice just to making sure that the group survives.