Safety check
The leader puts on his climbing shoes and ties into the rope. All harness buckles are fastened properly. Helmets on. There is a stopper knot in the end of the rope. The belayer has the rope threaded through the (carabiner locked) belay device with enough slack between the belayer and the climber for the climber to reach the first piece of protection. The climber has enough gear for the climb and anchor material.
There is a plan for the climb (e.g. set up a top rope). The rope is long enough.
Keep track with this checklist!
Commands
"Clipping" - the leader needs some slack quickly in order to clip the rope to a piece of protection (e.g. a quickdraw).
"Clipped" - the leader is letting the belayer know they have clipped the rope into the piece of protection.
Other commands are the same as in toprope belaying.
Spotting the climber
As the climber leaves the ground, the belayer should provide a "spot" for the climber. This means standing slightly back (not directly underneath the climber), with arms outstretched to either side, penguin-flipper hands, ready to guide the climber to the ground feet first if they fall. The belayer should be ready with a spot until the first piece of protection is clipped, at which point they should smoothly switch to belaying (you can lightly hold the rope with your thumbs while spotting to speed up this transition).
Letting out slack
Similar to toprope belaying, the belayer should have one hand always on the brake (brake hand) and the other hand above (guide hand). As the climber climbs, the belayer should feed slack by using both hands in concert (one above the device and one below the device). If you need to take in slack, use the PBUS method from toprope belaying.
Keep a closer belay (less slack in the rope) when the climber is close to the ground or anything else they might hit during a fall (such as a ledge). When the climber is free of obstructions, give just enough slack so that the rope goes straight out horizontally from your belay device and then up to the climber.
This will give the climber a softer catch if they do fall and give them enough slack to move around freely.
The belayer should also keep an eye on the climber to make sure they have not back clipped or z clipped and that the rope is not running behind their legs (which creates risk for the climber to be flipped in the event of a fall).
Keep track with this checklist!
Catching a fall
A lead fall can put a large amount of force on a belayer, even lifting them off the ground. Once the climber starts falling, the belayer should immediately move their other hand to the brake strand if both hands are not already on the brake. The belayer should maintain an athletic stance at all times and be ready to brace their feet against the rock in front of them if they get pulled off their feet (never letting go of the brake strand).
If there is not much rope in the system when the climber falls, the belayer will feel more force, compared to if there is more rope in the system and more rope drag. The leader will fall twice as far as they are above their last piece of protection, plus rope stretch. If their fall path is clear, the belayer can give a soft catch by letting themselves be pulled off the ground. If the leader is at risk of hitting something or rolling down a slab, the belayer should reel in as much slack as possible if they have time (never taking their hand off the brake) or step backwards to shorten the fall distance as much as possible.
Reaching the top
When the climber reaches the top, they should first clip a quickdraw into one of the bolts, and then set up a toprope anchor. After the anchor is set up and the rope clipped through the master point with two opposed locking carabiners, they can ask the belayer to lower them and clean the quickdraws as they go down.
