The participation of Australia means that all four members of the so-called Quad will be participating in the exercises for the first time since 2007. The Quad, or Quadrilateral Security Dialogue, is an informal strategic forum for the US, Japan, Australia and India, featuring semi-regular summits and information exchanges between the four nations. While not a formal military alliance like NATO, it is seen by some as a potential counterweight to growing Chinese influence and alleged aggression in Asia-Pacific. The collation has been denounced by Beijing as an anti-China bloc.