Explain what centered riding is and what are the keys to execution?

Centered riding is a teaching system developed by Sally Swift, first articulated in her 1985 book of the same name, that approaches riding improvement through body awareness, visualization, and the application of principles from anatomy, physics, martial arts, and somatic education to the specific challenges of communicating effectively with a horse from the saddle. It is not a riding style or a competitive discipline — it is a framework for understanding and developing the rider's body as an instrument of communication, applying equally to western and English disciplines, to beginners and to advanced riders who have reached a plateau that conventional instruction has not been able to move them past. The system is organized around four foundational concepts called the Four Basics — soft eyes, breathing, building blocks, and centering — each addressing a specific dimension of the rider's body and awareness. Soft eyes is the first basic. Hard eyes — the default state of riders concentrating intensely on a specific point — focus visual attention in a narrow beam that creates corresponding tension through the face, jaw, neck, and shoulders. Soft eyes expand the visual field to include peripheral vision while maintaining a forward direction. The neurological effect is immediate — the jaw releases, the neck softens, the shoulders drop, and the entire upper body becomes more relaxed and able to follow the horse's movement. Breathing is the second basic. Holding the breath under concentration or tension — which virtually every rider does in challenging situations — produces held tension throughout the entire trunk, stiffens the diaphragm and hip flexors, and locks the pelvis in a position that prevents it from following the horse's movement. Consciously exhaling at moments of effort or tension produces a softening of the entire trunk that the horse feels through the saddle. Building blocks addresses the alignment of the rider's body from the ground up using the image of stacked blocks — feet, ankles, knees, hips, shoulders, head — each balanced over the one below in a way that allows gravity to do the work of keeping the rider in position rather than requiring muscular effort to maintain incorrect alignment. Centering draws on concepts from martial arts to address the rider's relationship with her own center of gravity — located in the lower abdomen a few inches below the navel — as the physical and energetic hub of all movement and balance. A rider whose awareness and intention originate from the center makes large effective movements with very little visible effort because the core is organizing the movement and the limbs are following.