# Grandmaster Chess Online - AI Documentation & System Overview

> Website: Grandmaster Chess Online
> Tagline: Play Free Online Chess with Friends or Challenge AI
> Primary URL: https://www.grandmasterchess.online

## What is Grandmaster Chess Online?
Grandmaster Chess Online is a fast, responsive, web-based chess platform offering full standard FIDE chess rules, legal move validation, chess clocks, local pass & play, real-time multiplayer with shareable invite links/codes, and an adaptive 3-tier chess AI engine (Basic, Intermediate, Advanced). It also publishes original chess guides and strategy articles.

## Core Capabilities
- **Play Against AI**: Three levels of intelligence:
  - **Basic AI**: Beginner-friendly random/simple capture heuristic with low search depth.
  - **Intermediate AI**: Minimax algorithm with alpha-beta pruning, piece-square table positional evaluation, center control, and king safety.
  - **Advanced AI**: Deep evaluation engine with tactical calculations, piece activity, mobility, and positional awareness.
- **Play With Friends (Real-Time Multiplayer)**: Instant private room generation with 6-character room codes and one-click shareable invite URLs. Real-time move synchronization, chess clock countdowns, draw offers, resignations, and rematch workflows.
- **Local Two-Player Chess**: Pass-and-play mode on the same desktop or mobile device with flipping board options.
- **Chess Clock Controls**: Bullet (1+0), Blitz (3+0, 5+0), Rapid (10+0, 15+10), and Untimed casual matches.
- **Move History & PGN**: Standard algebraic notation (SAN) tracking, move list scrolling, position evaluation bar, and PGN export/download.
- **Board Customization**: Themes (Wood Classic, Modern Slate, Obsidian Dark, High Contrast) and customizable piece styles.
- **Chess Learning Center**: Dedicated guides on standard chess rules, opening principles, and tactical strategies.
- **Chess Blog**: Regularly published guides covering openings, tactics, AI strategy, time controls, and rules.

## Important URLs
- Homepage: `/`
- Play vs AI: `/play/ai`
  - Basic Difficulty: `/play/ai/basic`
  - Intermediate Difficulty: `/play/ai/intermediate`
  - Advanced Difficulty: `/play/ai/advanced`
- Play with Friends: `/play/friends`
- Local Pass & Play: `/play/local`
- Chess Rules Guide: `/learn/chess-rules`
- Chess Openings: `/learn/chess-openings`
- Chess Strategies: `/learn/chess-strategies`
- FAQ: `/faq`
- Dashboard & Stats: `/dashboard`
- Blog Index: `/blog`
- Blog Categories: `/blog/category/{category}`

## Chess Engine Architecture
The platform utilizes an abstracted `ChessEngine` layer (`BasicEngine`, `IntermediateEngine`, `AdvancedEngine`) interacting with FEN positions and returning SAN moves, enabling future neural network or Stockfish WASM integrations.
Server-side authoritative move validation guarantees game integrity for multiplayer rooms.

## Content & Publishing
Blog articles are authored editorially, published with full publish/update dates, and structured with Article and FAQPage schema for AI answer engines. Articles link contextually to the relevant play/learn pages they reference.