Shogi, or Japanese Chess, is a great and original Chess variant created in Japan. It was the first Chess variant which introduced the "drop" rule, implemented in Loop Chess as well - captured pieces could be returned to the board and player's own.
Start position and game object
Shogi is played on a square 9x9 uncheckered board. Each player starts the game with these pieces: 1 king, 1 rook, 1 bishop, 2 gold generals, 2 silver generals, 2 knights, 2 lances and 9 pawns. The starting position is shown on the following picture:
Unlike western chess, all pieces are the same colour and the same irregular pentagon shape. The loyalties are determined by their directional headings.
The object of the game is to give a checkmate to the opponent's king, just like in standard Chess.
Movement of pieces
All pieces in Shogi use the same rules for both moving and capturing enemy pieces. The last three rows from each player's perspective are called promotion zones and when any piece (except kings and gold generals) reaches them, they can be promoted to the corresponding promoted piece with different moving abilities.
A king moves one space vertically, horizontally or diagonally. As in standard Chess, a king is not allowed to make a move to a position which is being attacked by an enemy piece. If a king is being attacked (is in check), the corresponding player must cancel the check immediately. If it is not possible, the player loses the game.
A golden general moves one space horizontally, vertically or diagonally forward.
A silver general moves one space diagonally or straight forward. A promoted silver general moves as the gold one.
A knight moves one space straight forward, followed by one space diagonally forward, it may leap over occupied squares. A promoted knight moves as the gold general.
A lance moves any number of spaces straight forward. A promoted lance moves as the gold general.
A bishop moves any number of spaces diagonally. A promoted bishop combines the moves of a bishop and a king.
A rook moves any number of spaces vertically or horizontally. A promoted rook combines the moves of a rook and a king.
A pawn moves only one space forward. A promoted pawn moves as the gold general.
How to promote pieces
When a pieces reaches the promotion zone, the player has an option to promote. If so, a target promoted piece is displayed over the game board and when the player wants to make a promotion, clicks on the offered piece, otherwise submit the move without any other action.
The earned promotion (in the previous point) can be postponed to a later move, as long as this move begins inside the promotion zone. It doesn't matter when such move ends.
When a piece moves to a row where they cannot continue to move (the last row for pawns, lances and knights, or the row before the last row for knights), it must be promoted immediately.
If a promoted piece is captured, it turns back to its unpromoted version.
A piece dropped to the promotion zone cannot be promoted immediately, it must make at least one normal move first.
How to drop pieces
Instead of making a normal move, a player can choose one of captured pieces (on his/her side) and place it to an empty square of the board as his/her own piece (similar to Loop Chess).
A pawn may not be dropped to a column which already contains another unpromoted pawn of the same player.
A piece cannot be dropped to a square from which it couldn't make any legal moves (pawns, lances and knights on the last row, or knights on the last but one row).
It is not allowed to give a checkmate by dropping a pawn.
Other important rules
A game is won by checkmating the opponent's king. Because of the drop rule, a stalemate (which would mean a draw) is highly unlikely to reach.
Perpetual check is forbidden. The player who causes such situation is obliged to break it off.