The ATP is the worldwide executive organism of the men's professional tennis circuit. The circuit consists of 66 tournaments in 32 countries that give out between 3 million and 325,000-dollar prices. The ATP does also organize the Challenger tournaments, where many of the young players win their first matches and tournaments. Every year around 90 events are organized worldwide, and their prices in cash go from 50,000 to 125,000 dollars. The ATP has two systems for world qualifications. The first one is the Champions Race, and it was first used in January 2000. Players start the year with no points and accumulate them throughout the season from 18 tournaments: the four Grand Slams, the nine tournaments corresponding to the Mutua Madrileña Masters Madridand the best five results within the International Series tournaments. This qualification system determines which 8 players will play the ATP Masters Series, that is November's great final of the season, that will be held in Shanghai this year.
The mathematical qualification system (old ranking) is known as the ESP (Entry System Position). Computer ranking points are awarded every Monday with the best 18 results for 52 weeks. This is the basis both for the acceptance of entries and for the determination of seeded players. Points are awarded based on the total price money of the tournaments.