When did the Michelin Guide begin to award stars for fine dining establishments?

The Michelin Red Guide is the oldest European hotel and restaurant reference guide, which awards Michelin stars for excellence to a select few establishments. The acquisition or loss of a star can have dramatic effects on the success of a restaurant. The guide began to award stars in 1926. Initially, there was only a single star awarded. Then, in 1931, the hierarchy of zero, one, two, and three stars was introduced.