Somebody else can explain better, but stars are rating systems for international events. 4 stars are the highest rating of difficulty, usually a tougher course than the Olypmics.
Ah, found it:
International events have specific categories and levels of competition and are conducted under the rules of the FEI
(Concours Complet International, or International Complete Contest) is one such category and defines a three-day event that is open to competitors from any foreign nation as well as the host nation.
- CCI : International Three-day event (Concours Complet International)
- CIC: International One-day event (Concours International Combiné)
- CCIO: International Team Competitions (Concours Complet International Officiel). Includes the Olympics, the World Championships, the Pan Am Games, and other continental championships
The levels of international events are identified by the number of stars next to the category; there are four levels in total. A CCI* is for horses that are just being introduced to international competition. A CCI** is geared for horses that have some experience of international competition. CCI*** is the advanced level of competition.
The very highest level of competition is the CCI****, and with only six such competitions in the world (Badminton
, Rolex Kentucky
, Luhmuhlen Horse Trials
, and the Stars of Pau
) it is the ultimate aim of many riders. The World Championships
are also considered CCI****. Rolex offer a financial prize for any rider who can win three of the biggest competitions in succession. These are Badminton, Burghley and Kentucky. So far, Pippa Funnell is the only rider to do this. Andrew Hoy did come close, however, and in 2010 Oliver Townend was competing for this coveted "Grand Slam" at Rolex Kentucky when he suffered a fall at obstacle #20 which eliminated him from competition.
One, two and three-star competitions are roughly comparable to the Novice, Intermediate and Advanced levels of British domestic competition, respectively, and to the Preliminary, Intermediate, and Advanced levels of American domestic competition, respectively.