You may play anyone who accepts your invitation or invites you to play.
Many players list their preferences on the matchboard and on their personal information cards.
Please respect players' stated preferences. Guests may not invite robot players, including SnowieBlizzard, SnowieStorm, SnowieFlake, MeltedSnowie, and MrHyperbot. Once the checkers are displayed, it is good form to greet your opponent. Remember that you may be playing someone on the opposite side of the world, who does not feel comfortable speaking your language.