V is the owner of a small jewellery business which deals exclusively in pearls.

V is the owner of a small jewellery business which deals exclusively in pearls. The business has built up an excellent network of suppliers which deliver a steady stream of high quality pearls to its workshops, where a team of highly skilled craftsmen turn basic pearls into items of jewellery. V feels that no other company has such a talented and valuable workforce and believes their skills are rare and difficult if not impossible to imitate. They are the key to the company's sustainable competitive advantage and success.

What is the approach to strategy which proposes that competitive advantage is achieved from the organisation's unique assets or competences?