Go Life and Death Problem Solver

A Java Swing application that solves Go (board game) life-and-death problems using alpha-beta minimax search. Built as a Master's dissertation project.

Prerequisites

• Java 21 or later

Building

Using the Gradle wrapper:

./gradlew build

Or with a system-installed Gradle (8.x+):

gradle build

Running

./gradlew run

Or run the built JAR directly:

java -jar build/libs/GoLifeAndDeath.jar

Usage

The application opens a 19x19 Go board with a control panel on the right.

Modes

Switch between modes using the Game Options radio buttons:

• Play against human -- Two players alternate clicking on the board to place stones.
• Play against computer -- Play moves against the AI engine. Choose the computer's colour (black/white) and configure search depth/breadth, then press START for the computer to move.
• Edit the Go Board -- Set up a custom board position for analysis.

Editing a Board

In edit mode you can:

1. Add white/black stones -- Select a stone colour and click intersections.
2. Clear spaces -- Remove individual stones.
3. Mark out of bounds -- Mark areas outside the problem region (click "Set Space to Out of Bounds" to fill all remaining empty space).
4. Set life/death group -- Click a stone to designate the group whose survival is being evaluated. A red dot marks the selected group.

Playing Against the Computer

1. Load or edit a problem position.
2. Select Play against computer.
3. Choose the computer's colour.
4. Set MAX DEPTH (search tree depth limit; 99 = essentially unlimited) and MAX BREADTH (number of candidate moves evaluated per level).
5. Press START if it is the computer's turn, or click the board to play your move.
6. Press PASS to skip your turn.

Loading and Saving Problems

• LOAD -- Opens a file chooser to load a .txt problem file. Sample problems are included in the goProblems/ directory.
• SAVE -- Saves the current board position and description to a file.

Problem File Format

Problem files are plain text:

<19 rows of 19 characters each, top row first>
<turn>,<lifeRow>,<lifeColumn>
<optional description>

Characters: x (black), o (white), - (empty), * (out of bounds).

Project Structure

src/main/java/com/golifeanddeath/
  GoMain.java                  Entry point
  model/
    GoBoard.java               Board state representation
    GameHistory.java           Move history for Ko detection
  engine/
    AlphaBetaDB.java           Alpha-beta minimax search engine
    BoardEvaluator.java        Static board evaluation heuristics
    MoveChecker.java           Move validation and capture logic
    NextMoves.java             Candidate move generation
  ui/
    GoGUI.java                 Swing GUI and event handling
    BoardImage.java            Board rendering
  io/
    GoFileHandler.java         Load/save problem files
goProblems/                    Sample life-and-death problems