Professional sumo is divided into 6 ranked divisions. Wrestlers are promoted and demoted within and between these divisions based on the merit of their win/loss records in official tournaments. For more information see kachikoshi and makekoshi. Wrestlers are also ranked within each division. The higher a wrestler's rank within a division is, the stronger the general level of opponents he will have to face becomes. According to tradition, each rank is further subdivided into East and West, with East being slightly more prestigious, and ranked slightly higher than its West counterpart. The divisions, ranked in order of hierarchy from highest to lowest, are as follows: