Frequently asked questions.

Q: Is it free?
A: Yes. All programs and services from this site are free!!!

Q: Where can I get java?
A: Java Runtime Environment available here

Q: How can I play with another person over the Internet?
A: You can play network checkers on PC or on Android devices.

Q: How rating works
A: Elo rating system is used

  • Bots and guests don't have rating and don't affect on statistics and rating of registered users
  • Rating and player statistics are updated only if more than one move has been done in the game
  • Initial rating is 800
  • Rating calculation:
    E = 1 / (1 + 10 ^ ((R_opp - R) / 400.0)) - win probability, or the same as expected game result (0 - lose, 1/2 - draw, 1 - win)
    R_new = R + K * (S - E) - new rating
    R - players rating
    R_opp - opponents rating
    K - coefficient. 30 for new players who played 30 games or less, 15 for players with rating less than 2400, 10 for others
    S - game result

Q: Useful info about online game

  • A draw offer can be accepted only till next opponent move. If you don't accept the draw offer no special actions are required. After next your move the draw offer is rejected