Bouldering is a form of rock climbing performed on short walls or rock formations called "boulders," without the use of ropes or harnesses. Climbers tackle short, powerful sequences known as "problems," landing on thick crash pads or padded gym floors if they fall.
Indoor bouldering takes place in dedicated bouldering gyms with walls up to about 4.5 metres high. Routes are marked by coloured holds — climbers follow a single colour from the marked start to the finish. Outdoor bouldering happens on natural rock, with portable crash pads carried to the boulder.
Bouldering uses the V-scale (in the US, UK, and most of the world) or the Font scale (in France and parts of continental Europe) to grade difficulty. Beginners typically start at VB or V0 and progress to V2–V3 within a few months of regular climbing. Bouldering is the easiest entry point into climbing — no harness, no belayer, just shoes, chalk, and the wall.