Head Reading at Lawn Bowls: The Enemy Cluster and the Need for Cover

Sometimes when you are ‘up’ in a head, the greatest tactical danger is a cluster of enemy bowls somewhere behind the jack.  The level of danger is usually proportional to the largest area contained within a polygon formed by joining the bowl positions by imaginary straight lines. For example, three bowls close together can be visualized being in a triangle; four enemy bowls close together can be visualized as being either in the quadrilateral or the largest triangle that can be made from the positions of any three of the bowls.

Even a grouping of two opposition bowls behind the jack can represent an incipient cluster because if the other side trails the jack back towards these bowls, the delivered bowl can often become part of the cluster.

The danger is that the jack may be moved to a location where all these opposing bowls will become counters.  The resolution of this danger is for your side to deliver a bowl into this polygon shaped area.