Si started his hairdressing career by working for Vidal Sassoon in the famous west end of London. His specialties were high fashion hair cutting and styling, colouring, colour correction, and multi-colour highlights while working there. He worked at several fashion shows and educational seminars with Vidal Sassoon, in conjunction with well-known clothes fashion designers.
Early in his career, Si looked after many celebrities' fashion wigs. It was this that began his interest in wigs and hair replacement. Studying many wig-making techniques led him to different parts of Asia, where he perfected the skills of constructing wigs using different types of lace bases and knotting techniques. As a result, he became a master at creating high-end custom-made designs to meet every client's needs and tastes.