Rules of Ridge Soaring

When soaring a hang-glider or paraglider, there is a simple rule that dictates the traffic flow – follow the ridge with the slope close on your right, return with the slope farther away to your left. This adheres to the international standard: when approaching an aircraft, avoid a collision by turning to pass on the right.
The pilot with the ridge/mountain on their right has the right of way. Pass other pilots from behind between them and the hill.

Pilots approaching head-on should both yield to their right. This keeps pilots from having to guess which direction the other is going to turn.
The pilot with the ridge on their right has the right of way. Usually the pilot with the ridge on their right is also closer to the hill and has no room to allow another pilot to pass between them and the hill. Therefore, the pilot with the hill on their left is responsible for making space and moving further away from the hill.