The most popular historical variant of shogi played on a 12x12 board
This article assumes certain knowledge of shogi rules, but if this assumption is incorrect, you can learn shogi here.
I will list the rules here in a concise way, but if you want to read a great explanation of chu shogi rules, that match the rules used on lishogi, I recommend this article by Dr Eric Silverman. Another useful source might be wikipedia, but keep in mind, that wikipedia mentions also alternative rules to Japanese Chu Shogi Association.
If you want a great explanation in a video form, I recommend this 2 part video series by CouchTomato posted on PyChess YouTube channel.
Just like in standard shogi, players alternate making a move. But unlike in standard shogi, after a piece is captured it is removed from the game completely and cannot be dropped back on the board.
Promotion zone consists of the farthest 4 ranks from your base camp. You can promote ONLY when you enter the promotion zone from outside the promotion zone or if you capture opponent's piece inside the promotion zone or while moving outside the promotion zone.
Pawns and lances get another chance to promote when they reach the last rank. Unlike in standard shogi, this promotion isn't forced and you can decide to leave the piece stuck on the last rank.
There are pieces you are familiar with from standard shogi, but also many new ones.
Some pieces have lion power - meaning they can move twice per round. These pieces are Lion (promoted or unpromoted), Falcon and Eagle. Let's look at them in detail.
Lion can either move to any square within a distance of two squares. It will jump over any pieces in the way (similarly to knight) or move to any surrounding square and then move again to another surrounding square. This allows you for example to make two captures, capture and return to your original square (called igui) or just pass a turn by moving to a neighboring square and back (called jitto).
There are relatively complex rules about capturing lions (promoted or unpromoted). The reason for this is to prevent players from simplifying the game by trading lions off. Let's look at the rules:
A lion can capture another lion only if:
- The lion is adjacent.
- The lion isn't protected.
- Significant capture (not a pawn or go-between) is made alongside the capture of lion.
If non-lion captures a opponent's lion, opponent cannot respond by capturing your lion with a non-lion piece on the next turn, even if the lion is unprotected.
If the lion is defended only by a pawn or go-between, and that pawn or go-between is captured on the first lion move, you still cannot capture the lion, although it is now undefended.
Falcon can also move twice per round, but in a limited range of it's two forward squares. Meaning it can jump to any of the 2 squares in front of it, move first to the square directly in front of it and then either continue forward or move back to its original square.
Similar to Falcon, but instead it can perform these move on the two forward diagonals.
- Pawn -> Promoted pawn
- Go-Between -> Elephant
- Side-Mover -> Boar
- Vertical-Mover -> Ox
- Rook -> Dragon
- Bishop -> Horse
- Dragon -> Eagle
- Horse -> Falcon
- Elephant -> Prince
- Chariot -> Whale
- Tiger -> Stag
- Kirin -> Lion
- Phoenix -> Queen
- Lance -> White Horse
- Leopard -> Bishop
- Copper -> Side Mover
- Silver -> Vertical Mover
- Gold -> Rook
Not mentioned roles - King, Queen and Lion do not promote.
Pieces promote once, meaning you cannot promote an elephant you obtained from promoting a go-between.
Capturing All Royal Pieces
Unlike in shogi, your main objective isn't to checkmate your opponent, but to capture all their royal pieces.
Royal pieces are King and Prince.
This might seem odd at first, but checkmate is just a threat to capture on the next turn, that cannot be escaped, so it's actually very similar.
Another way to win is capture all opponent's other pieces and leave their single royal piece (king or prince) alone - BARING THEIR KING. But there are few more conditions:
- If you only have pawns or go-betwens. You first have to SAFELY promote them in order to win.
- If your opponent could bare your king on his turn, you do not win, instead it's draw.
- Pieces that are in a position where they can under no circumstances ever move again (last rank pawn/lance) do not count into these considerations.
If the same position repeats 4 times, the game is declared a draw.
But if starting from the first time the repetition occurred you continue to make moves that threaten opponent's piece with capture, you will lose the game - similar to Perpetual check rule in standard shogi.
As mentioned in Bare King rule, if each player has only one royal piece left, the game is declared a draw.
No impasse rule is used in chu shogi, but players might agree to a draw.
Image with piece movements was provided by CouchTomato.
P.S. This article might change in the future, if you want to suggest an edit, please open an issue on GitHub.