Sound connection

Every game is a fight over control of the board. Control is often gained or lost by players exploiting each others connections. Making sound (as in healthy) connections means making connections that are less likely to be exploited.

As a counterexample, consider the unsound connection below.

Although the three pieces are connected by two bridges, these overlap in the center point, and if Blue occupies that point,

Red can only connect two of the three stones.

Soundness is not only non-overlapping connections. It is also the practice of grabbing territory when given the chance. For example, when joining two groups of pieces there are often several different moves which join the groups but claim territory in different ways.