Bario Rules
Bario is a chess variant invented by Panos Louridas in 1998. His website contains many examples and explanations. See also the discussion on chessvariants.com .
Undefined pieces on first ranks.
Queens, rooks, bishops and knights begin the game in a reserve below the board, because their location isn't determined yet. At each turn, you can either move something already defined on the board, or
- move a piece from your reserve to any question mark, and then
- move the now defined piece on the board.
Your pieces remain in an undefined state until they are moved.
An undefined piece gives check if some specialization giving check exists.
Details, special cases
At the first move, you must select a square for the king anywhere on the first rank — preferably in a corner. This deviates from the original intention of the author, but this way you will not need to castle later in the game. Click on a square to place the king.
If after your move all your pieces are defined (and weren't before), then all pieces on board revert to undefined state, unless:
- all your pieces (board + reserve) are now of the same type, in which case none is put back in reserve, or
- all opponent's pieces are of the same type, in which case they also remain defined.
If one of your undefined pieces is captured, you first have to choose which one was captured from the reserve: place it at the capture location.