Hexagonal chess variant played on an irregular hexagon.
More details about non-pawn piece movement: Hexagonal chessboards
Pawns move towards the opponent's side. They capture diagonally forward (in bishop's directions). They can move one, two or three fields from their initial position as far so they can reach the middle of the board in one move (see diagram below). After that they can move only one field at once. They promote on the opposite two edges of the board (marked by red on the diagram).
Castling is possible in the two directions (queenside and bishopside), and both can be short or long. When castling short the king moves two fields and the rook moves three, when castling long it is the other way around:
Short and long castling on queenside
Short and long castling on bishopside
Otherwise the rules of chess apply.
Isaak Grigorevich Shafran, 1939[wiki]