To find out what stairs you can currently challenge someone in, first go to the Main Stairs Page, then click on "Show your stairs only" link. The ones in BOLD are ones you can make a challenge in. .
Why there are ladders (for example as in http://brainking.com/en/Stairs?trg=3&tri=223, and there are others) where there are two players, no games playing, no games recently played against each other and yet you have no player to challenge?
(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)