shogi

A simple shogi engine for Dart and Flutter. This engine can be combined with flutter_shogi_board to render static game board positions, tsume problems or shogi castles.

Shogi (将棋) is a two-player strategy board game native to Japan, belonging to the same family as chess and xiangqi.

Presently the package is very basic in which it can determine the static board position for a given game and move pieces from one position to another. As it is still highly experimental, 0.0.x versioning is used.

Getting Started

Import the package

To import this package, simply add shogi as a dependency in pubspec.yaml

dependencies:
  shogi:

Example

import 'package:shogi/shogi.dart';

void main() {
  final gameBoard = ShogiUtils.initialBoard;
  gameBoard.printToConsole(useJapanese: false);
}

|l |n |s |g |k |g |s |n |l |
|  |r |  |  |  |  |  |b |  |
|p |p |p |p |p |p |p |p |p |
|  |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |
|P |P |P |P |P |P |P |P |P |
|  |B |  |  |  |  |  |R |  |
|L |N |S |G |K |G |S |N |L |

Importing a Game Board

SFEN

A game board can be imported using a SFEN ascii string:

final sfenString = 'lnsgkgsnl/1r5b1/ppppppppp/9/9/9/PPPPPPPPP/1B5R1/LNSGKGSNL b -';
final gameBoard = ShogiUtils.sfenStringToGameBoard(sfenString);

BOD

Alternatively, a game board can be imported using a BOD string:

final bodString = '''
後手の持駒：なし
  ９ ８ ７ ６ ５ ４ ３ ２ １
+---------------------------+
|v香v桂v銀v金v玉v金v銀v桂v香|一
| ・v飛 ・ ・ ・ ・ ・v角 ・|二
|v歩v歩v歩v歩v歩v歩v歩v歩v歩|三
| ・ ・ ・ ・ ・ ・ ・ ・ ・|四
| ・ ・ ・ ・ ・ ・ ・ ・ ・|五
| ・ ・ ・ ・ ・ ・ ・ ・ ・|六
| 歩 歩 歩 歩 歩 歩 歩 歩 歩|七
| ・ 角 ・ ・ ・ ・ ・ 飛 ・|八
| 香 桂 銀 金 玉 金 銀 桂 香|九
+---------------------------+
先手の持駒：なし
''';
final gameBoard = ShogiUtils.bodStringToGameBoard(bodString);

Piece Movement

KIF

Piece movement can be specified using KIF notation:

var gameBoard = ShogiUtils.initialBoard;
final kif = '''
1 ７六歩(77)
2 ３四歩(33)
3 ２二角成(88)
4 同　銀(31)
5 投了
''';
final moves = KIFNotationConverter().movesFromFile(kif);
gameBoard = GameEngine.makeMove(gameBoard, moves.first);
gameBoard.printToConsole();

Custom

Alternatively, piece movement can be specified using the custom notation {Player}{PieceType}{CurrentPosition}{Movement}{TargetPosition}{Promotion}.

{Promotion} is optional, while if {Player} isn't specified, Sente is chosen by default. {CurrentPosition} is needed for all movement types, except drops. Movement is denoted by -, x and *, that is, simple movement, capture and drop respectfully. Some examples:

Type Example Explanation
Simple movement ☗P77-76 Sente's pawn moves from 77 to 76.
Capture ☗P75x74 Sente's pawn moves from 75 to 74 and captures the piece at 74.
Drop ☗S*34 Sente's drops a silver from in hand onto 34.
Combined ☗S34x33+ Sente's silver moves from 34 to 33, captures the piece at 33 and is promoted.

Thus, given an initial board for Sente, a Yagura castle could be build using the following moves:

1: ☗P77-76
2: ☗S79-68
3: ☗S68-77
4: ☗G69-78
5: ☗P57-56
6: ☗K59-69
7: ☗G49-58
8: ☗B88-79
9: ☗P67-66
10: ☗G58-67
11: ☗B79-68
12: ☗K69-79
13: ☗K79-88

Future Plans

  • Investigate Bitboards
  • Determine if a move is valid
  • Simple Computer AI

Raising Issues and Contributing

Please report bugs and issues, and raise feature requests on GitHub.

To contribute, submit a PR with a detailed description and tests, if applicable.

Libraries

shogi