Bridge

A bridge, or a two-bridge, is a type of connection between two pieces. It is the equivalent of a diagonal step on a chess board.

R4, C4, Hb2, Hc3

The idea is that when the opponent "intrudes" on the bridge by moving in one of the empty hexes between the pieces, you simply move in the other. Bridges are often very strong, and a quick way to advance across the board. They can sometimes be exploited.