It is an assessment of racehorses which was issued by the International Federation of Horseracing Authorities (IFHA) in August 2006.
These countries are generally in the Southern Hemisphere, although some areas covered, such as Hong Kong and the United Arab Emirates, are actually north of the equator.
It is judged that these weights would equalize the abilities of the horses if carried in a theoretical handicap race.
They also show the top performers in various subdivisions of each group, which are defined by the distances of races, and the surfaces on which they are run.
The IFHA recognizes five distance categories — Sprint, Mile, Intermediate, Long and Extended — identified by the acronym "SMILE".