The basis of a sculptor's 12 year training is drawing. Apprentices spend two years drawing and thoroughly mastering Tibetan art's huge range of figures and symbols. The two principal techniques of the metal sculptor's work are repoussé and chasing. Repoussé is used to shape the metal from behind to form a raised design, chasing is used to refine that design on the front of the work by sinking and engraving the metal. Once apprentices begin to show talent and skill in repoussé and chasing, they join the team fulfilling the studio's commissions. Working under the rigorous care and supervision of the master sculptor and his assistants, their work steadily improves.