Chess Library - Overview

PonzianiComponents contains a chess library helping to create chess-related applications. This library is independent of Blazor and can be used in any .Net 6 based application.

The library is contained in namespace PonzianiComponents.Chesslib

Here are some examples, how to use it:

Move generation

using PonzianiComponents.Chesslib;

//Create a position object from FEN string
Position pos = new("rnbqkbnr/pp2pppp/3p4/1Bp5/4P3/5N2/PPPP1PPP/RNBQK2R b KQkq - 1 3");
//Get all legal moves
var moves = pos.GetMoves();
//Output moves in uci- and in SAN-Notation
foreach(var move in moves)
{
    Console.WriteLine(move.ToUCIString() + " " + pos.ToSAN(move));
}

The output should be something like

b8c6 Nc6
b8d7 Nd7
c8d7 Bd7
d8d7 Qd7

Handling Chess Games

The Game object allows to process complete chess games:

using PonzianiComponents.Chesslib;

//Creates a new game 
Game game = new();

//Apply moves (first 3 moves from the immortal game https://en.wikipedia.org/wiki/Immortal_Game)
game.Add(new("e2e4"));
game.Add(new("e7e5"));
game.Add(new("f2f4"));
game.Add(new("e5f4"));
game.Add(new("f1c4"));
game.Add(new("d8h4"));

//It's now white's turn to make the 4th move
Console.WriteLine($"Movenumber:         { game.Position.MoveNumber }");
Console.WriteLine($"SideToMove:         { game.SideToMove }");

//White is in check, this can be tested with the API
Console.WriteLine($"Checked:            { game.Position.IsCheck }");

//It's now white's turn to make the 4th move
Console.WriteLine($"Movenumber:         { game.Position.MoveNumber }");

//Let's get the movetext in SAN-Notation
Console.WriteLine($"Startposition:      { game.StartPosition }");
Console.WriteLine($"Movetext:           { game.SANNotation() }");

//Get the position from 2nd move after white played 2. f2f4
Position pos = game.GetPosition(2, Side.BLACK);
Console.WriteLine($"Fen after 2. f2-f4: { pos.FEN }");

//We can also output the position as ASCII graph
Console.WriteLine(pos.ASCII());

This should give

Movenumber:         4
SideToMove:         WHITE
Checked:            True
Movenumber:         4
Startposition:      rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1
Movetext:           1. e4 e5 2. f4 exf4 3. Bc4 Qh4+ *
Fen after 2. f2-f4: rnbqkbnr/pppp1ppp/8/4p3/4PP2/8/PPPP2PP/RNBQKBNR b KQkq - 0 2
  a   b   c   d   e   f   g   h
---------------------------------
| r | n | b | q | k | b | n | r | 8
---------------------------------
| p | p | p | p |   | p | p | p | 7
---------------------------------
|   |   |   |   |   |   |   |   | 6
---------------------------------
|   |   |   |   | p |   |   |   | 5
---------------------------------
|   |   |   |   | P | P |   |   | 4
---------------------------------
|   |   |   |   |   |   |   |   | 3
---------------------------------
| P | P | P | P |   |   | P | P | 2
---------------------------------
| R | N | B | Q | K | B | N | R | 1
---------------------------------

Working with PGN files

Ponziani also offers methods to read and write PGN (Portable Game Notation) files.

Reading is simple. You can either read a PGN-File from disk with

PGN pgn = new PGN(fileName);
var games = pgn.LoadAsync().Result;

or get the pgn from somewhere else as string

//Get the last 10 games of Magnus Carlsen (alias DrNykterstein) as pgn from lichess
HttpClient client = new HttpClient();
string pgn = client.GetStringAsync("https://lichess.org/api/games/user/DrNykterstein?tags=true&clocks=false&evals=false&opening=false&max=10&perfType=ultraBullet%2Cbullet%2Cblitz%2Crapid%2Cclassical").Result;
//Parse pgn
var games = PGN.Parse(pgn);
//Output some header information for each game
foreach (var game in games)
{
    Console.WriteLine($"{ game.White } - { game.Black } {game.Result} Moves: {game.Position.MoveNumber}");
}
//Get final position of last game
Position pos = games.Last().Position;
Console.WriteLine($"Final Position: {pos.FEN}");
//and output it as ASCII
Console.WriteLine(pos.ASCII());

This code snippet should output something like

DrNykterstein - may6enexttime WHITE_WINS Moves: 28
may6enexttime - DrNykterstein BLACK_WINS Moves: 61
DrNykterstein - may6enexttime WHITE_WINS Moves: 69
may6enexttime - DrNykterstein BLACK_WINS Moves: 38
DrNykterstein - may6enexttime WHITE_WINS Moves: 27
may6enexttime - DrNykterstein BLACK_WINS Moves: 29
DrNykterstein - may6enexttime WHITE_WINS Moves: 34
may6enexttime - DrNykterstein BLACK_WINS Moves: 60
DrNykterstein - may6enexttime WHITE_WINS Moves: 36
may6enexttime - DrNykterstein BLACK_WINS Moves: 34
Final Position: 6k1/5pp1/1pp4p/8/1P1N4/3Q4/3p1PPP/2q1rRK1 w - - 4 34
  a   b   c   d   e   f   g   h
---------------------------------
|   |   |   |   |   |   | k |   | 8
---------------------------------
|   |   |   |   |   | p | p |   | 7
---------------------------------
|   | p | p |   |   |   |   | p | 6
---------------------------------
|   |   |   |   |   |   |   |   | 5
---------------------------------
|   | P |   | N |   |   |   |   | 4
---------------------------------
|   |   |   | Q |   |   |   |   | 3
---------------------------------
|   |   |   | p |   | P | P | P | 2
---------------------------------
|   |   | q |   | r | R | K |   | 1
---------------------------------

To write PGN the Game class offers method ToPGN() which returns the PGN as string.

//Creates a new game 
Game game = new();
//Set game header data
game.White = "Adolf Anderssen";
game.Black = "Lionel Kieseritzky";
game.Date = new DateTime(1851, 6, 21).ToShortDateString();
//Apply moves (first 3 moves from the immortal game https://en.wikipedia.org/wiki/Immortal_Game)
game.Add(new("e2e4"));
game.Add(new("e7e5"));
game.Add(new("f2f4"));
game.Add(new("e5f4"));
game.Add(new("f1c4"));
game.Add(new("d8h4"));
//export to PGN
string pgn = game.ToPGN();
Console.WriteLine(pgn);

This will print

[Site ""]
[Date "21.06.1851"]
[Round ""]
[White "Adolf Anderssen"]
[Black "Lionel Kieseritzky"]
[Result "*"]
[ECO "C33"]
[Opening "KGA: Bishop's Gambit"]
[Termination "unterminated"]

1. e4 e5 2. f4 exf4 3. Bc4 Qh4+ *

to the console.

Please note: The ECO and Opening tags haven't been set automatically. They were added automatically. ECO classification is another feature of the API.