Improving belay anchors at a stance
Sometimes we need a way of improving belay anchors at a stance on a multi-pitch rock climb. There could be a number of reasons for this situation arising. Perhaps the obvious and appropriate belay stance has too few anchors available, or perhaps the rock itself at the stance is poor. Whatever the reason, we are faced with the choice of taking the risk of using poor anchors (and therefore having a weak overall belay stance) or finding some other way to improve the overall security of the belay.
This trick can sometimes, although by no means always, provide a solution.
First, place whatever gear is necessary to use the anchors that are immediately available on the belay stance/ledge. Then link these together, perhaps by using an equalised sling, and use the whole set-up as a runner so that you can climb safely a little further up the route above the belay stance. Find some better gear placements that would have been out of reach from the belay stance and then return to the stance and continue to build your main belay, extending it as required and incorporating these higher, better anchors into the system.
This technique is unlikely to be workable in certain circumstances, however. For example, it may be plainly obvious that the first part of the next pitch will offer little in the way of additional anchor placements. In other situations, the climber may have already used up all the equipment that would allow him to extend these anchors so that they can be connected to the belay stance (for example all long slings have been used and the amount of rope run out on the pitch means that not enough rope is available).