A figure four is a climbing move where the climber, while hanging from a hold, hooks one leg over the opposite forearm — looping the back of the knee over the arm — and uses the leg as a leverage point to push their body upward toward a higher hold. The position resembles the number 4 in profile.
Figure fours are commonly used in dry tooling, ice climbing, and some highly overhanging dry routes. They let the climber gain meaningful reach without launching dynamically — essential when the holds are sharp ice tools and dynamic moves are dangerous. The technique demands flexibility, core strength, and the ability to commit body weight to an unusual position.
The related "figure nine" is the same idea with the leg hooked over the same-side arm rather than the opposite — even more extreme and harder to reverse. Both moves are advanced and rarely seen in beginner climbing, but they show up frequently in professional ice and dry-tooling competitions where they let the climber bypass missing hooks or rest mid-route.