Chess attack is a 5x6 board chess variant invented by the Norwegian game designer Werner Kling in 2008. The game was endorsed by Magnus Carlsen and Alexandra Kosteniuk.
Played on a 5x6 board, each player starts with 5 Pawns, 1 Rook, 1 Knight, 1 Bishop, 1 Queen and 1 King.
Castling: yes.
"En passant" capture: yes.
Double move for Pawns (start): yes.