Strategy notes for Chu Shogi
modified March 12, 2021.update: found this https://web.archive.org/web/20101226050102/http://www.colina.demon.co.uk/books.pdf
chu shogi blogs:
- https://drericsilverman.wordpress.com/2020/04/05/chu-shogi-part-i-how-to-play/
- https://chushogilionhawk.wordpress.com/
chu shogi videos:
- https://www.youtube.com/watch?v=fnJSSd1WCFk
- https://www.bilibili.com/video/BV157411K7nc/
- https://www.youtube.com/watch?v=d245RsjOU64
- https://www.youtube.com/channel/UC0n0caBL4jq8d98QHSpig6A
- https://www.nicovideo.jp/user/3018550/video
I got interested in Chu Shogi (a 12x12 shogi variant) a while back. I was pretty surprised at the lack of strategy-related resources surrounding this game so I decided to write some.
I’m currently running xboard and playing against the HaChu engine. Here’s what I’ve gathered from playing against HaChu 0.21:
Early game
- Early game, the horse is the most powerful piece. Moving the e and h pawns opens up the center diagonals for your horse.
- The e and h pawns are very important. Often you advance them both first to protect the square on 6th rank – if you don’t, the opposing lion can move to those squares in 2 turns and eat your go-betweens. Alternatively you can defend both go-betweens with your lion, but doing this early hurts your setup since it blocks the advance of your center pawns (and the opponent can easily develop while threatening your lion with e.g. horse to j9 or bishop to k10)
- The go-betweens (files d and i) block some very hard-to-move pawns, so you can treat those pawns as walls that will not move ever. So there is a wall between the center and the sides. The go-between is also very hard to move – if you advance the go-between on d5, the opponent can easily move their h pawn (which is a standard opening anyways) and have their horse or bishop threaten c4 and d5.
- After pushing the e and h pawns as well as the copper/silver/leopards on either side, you want to move the side pawns. Make some room by pushing side movers forward
- If the opponent shoves a horse forward early, can usually remove its presence by pushing and sacrificing a horse of your own (if they capture it with the horse, you capture back with bishop)
Early to midgame
- You want to get your bishops out to pressure squares! Do this by moving the horse – either diagonally towards the center or diagonally towards the side. Exposing the left bishop pressures the right side, and vice versa.
- The c, e, h, j pawns are protected by the rook/dragon behind them, no matter how far up they advance. This means they can threaten those files pretty easily – if you sacrifice that pawn, suddenly you have control of the whole file via the rook or dragon. The same goes for the b and k pawns (which hide the vert mover), though those are more often used in side battles.
- A battle on a side is meant to force your opponents to divert resources from the center. The goal is to clean out their b file, at worst you threaten an exchange of vert movers (which you can do whenever you need to force opponent pieces to the side). The basic setup (e.g. for the left side) is to advance the a,b,c pawns once and have a leopard defending all 3 right behind the b pawn. You advance the leopard by moving the side mover up. Alternatively you can have a copper behind the c pawn, which is easier to set up in the case when your horse is out of the way already. If you do this, you can develop your bishop by moving your vert mover down one square (so the leopard defends it) and moving the bishop where it was.
- When do you bring out the lion? Typically I’ve found it makes sense to bring out the lion when you want to apply a lot of pressure on one side of the board. You also want to bring out the lion ASAP if your opponent has brought out the lion.
- Don’t think about capturing the lion until the board is almost clear. Lion chasing puts pressure, sure, but it’s super hard since lion capture rules don’t let you exchange protected lions, and also there are often better moves you can make (like moving your steppers). Lions will almost always survive until endgame.
- You might be tempted to ignore the steppers and only move your flashy powerful pieces (lion, horse, dragon). This is what I did at first, and it let me lock up most of the board. But what happens after the board is locked up and your big pieces are stuck in a standoff with your opponent’s big pieces? That’s where the steppers come in – they’ll step into the standoff and threaten your big pieces, forcing them to move. The player who can advance their steppers sooner, wins the standoff.
- The steppers you don’t want to move are: blind tiger, drunk elephant, and gold general. These will stay behind to protect the king until endgame. The steppers you absolutely want to move (it would be a mistake not to) are: silver general, copper general, ferocious leopard. The phoenix also works as a powerful stepper, as mentioned earlier.
- I find it really hard to make use of pins, since the important pieces are so mobile they won’t put themselves behind a pin. This is less true in the endgame where you’re pinning against the (less mobile) king.
Midgame
- At this point your steppers are all advanced and everything is locked up and you have three pieces defending one pawn that’s being attacked by three pieces, and both lions are watching that pawn.
- Start castling! The Elephant, Tigers, and Golds are the only steppers that can move side-to-side, and are considered perfect for defense because of this.
- The AI always brings out their bishops to control the center, which makes sense since it’s a powerful ranging piece that you also aren’t too afraid to lose. In particular, you use bishops to threaten horses!
- Now that the steppers are here, you can start moving your now-protected go-betweens to add more pressure, and (most importantly) to open up space on the d- and i-files in your camp.
- The free king starts participating to defend big pieces. I’ve also seen the phoenix get brought out onto e4 or i4 (it’s like a long-range stepper). I don’t often see the ki-rin get brought out, it’s just not a very good piece.
- Undoubtedly an exchange happens (or a lion decides to feast) and a bunch of pawns are eaten. Remember the c, e, h, j pawns? Once those are eaten, your rooks and dragons enter the game, and can start wresting control of the middle ranks away from the lion. Don’t be afraid to move your rooks and dragons out, since the side movers should be protecting ranks 3 and 4.
- Now you start pressuring the lion. The rule for checking a lion is simple: putting anything on 8 squares around it often won’t threaten it even if that piece is protected, because the lion can capture without moving (igui). So the best pieces to check the lion with are ranged pieces – this includes the phoenix and ki-rin!
Mid- to endgame
- If you haven’t brought up your steppers by now, bring up your steppers if only to cover all the ground opened by pieces getting captured.
- If you’ve moved your phoenix on g2, consider moving the blind tiger on h2 to g2, to protect that king’s diagonal.
- Now you can start moving your ranged pieces (esp. rooks and dragons) into enemy territory! So you can have the option of capturing, promoting, and then instantly dying since the opponent’s camp is probably still well-protected.
FP takes on OOP design patterns