DragonKing: No computer understands the term "perpetual". It must be defined in a discrete math, for example 3 checks in a row (with the same position of all pieces) can be taken as a perpetual check.
(hide) If you want to play a game with an opponent of a similar level, you can define a required BKR range for a new game invitation. Then nobody with a BKR outside this range will be able to see/accept it. (Katechka) (show all tips)