Play away from thickness
The proverb "play away from thickness" is one of the most important strategic proverbs, perhaps even the most important. It has two aspects:
- When the opponent has a thick group in some part of the board, do not play close to that group, but stay away from it. A stone played close to a thick group will come under attack easily, while it doesn't affect the status of the group at all.
- When you have yourself a thick group in some part of the board, do not play close to that group, but play far away from it. A stone played close to your own thick group will only add marginal strength and hence is not efficient but leads to overconcentration.
Staying further away with b is also possible, or creating a higher position with c, or expanding to a big moyo with d or e.
here is overconcentrated. The corner stone is the one in need of development, not the thick group.
plays away from Black's thickness, and makes a corner enclosure. The effectiveness of Black's thickness is reduced and a Black move at a would be overconcentrated. Staying further away from the Black group, with b, or developing towards the other side, with c is also possible.
Any wider extension, such as , will invite a Black invasion. Allowing a Black invasion implies a loss for White because White will lose territory and gain influence, but the effectiveness of White's influence will be severely reduced by Black's thickness.
The way I learned this proverb is, "Do not approach strength", which is more general. In fact, "Do not play (too) close to strength," is even better, since it applies to one's own strength as well as the opponent's. -- Bill Spight