About Reversi Stone & Shadow
About Reversi Stone & Shadow
Reversi Stone & Shadow is a premium strategy board game built on the classic Othello/Reversi ruleset. Place black or white stones on the 8×8 board, flip your opponent's pieces, and control the most territory by the end. With a powerful Minimax AI with Alpha-Beta Pruning, three difficulty levels, stunning visual themes, and a local 2-player mode, this is the definitive browser Reversi experience. No download needed — play free instantly!
How to Play Reversi
- The board starts with 4 stones in the center — 2 dark and 2 light in a diagonal pattern.
- Players take turns placing a stone of their color on any valid empty square.
- A move is valid only if it sandwiches at least one opponent stone between your new stone and another of yours.
- All sandwiched opponent stones are flipped to your color instantly!
- If you have no valid moves, your turn is automatically passed.
- The game ends when neither player can move — the player with the most stones WINS!
Game Features
- 🤖 AI with Minimax + Alpha-Beta Pruning — Intelligent AI that plans multiple moves ahead
- 🟢🟡🔴 3 AI Difficulty Levels — Easy (random play), Medium (depth 4), Hard (depth 6 + corner priority)
- 👥 Local 2-Player Mode — Challenge a friend on the same device
- 🎨 6 Board Themes — Obsidian, Crimson (free) + Arctic, Amber, Neon, Violet (unlock with coins)
- 💡 Hint Button — Shows the AI-recommended best move when you're stuck
- ↩ Undo Move — Take back your last move for 20 coins (AI move also undone)
- 🪙 Coin Economy — Earn coins by winning: Easy +10, Medium +20, Hard +30
- 🏆 Win Tracking — Track your wins across all difficulty levels
- ✨ Piece Flip Animation — Smooth coin-flip animation when pieces are captured
- ⚫ Specular Stone Rendering — Glossy obsidian and pearl stone effects
- 📱 Responsive Design — Works on desktop, tablet, and mobile
- 💾 Progress Saved — Coins, unlocked themes, and win stats persist between sessions
AI Strategy Explained
- 🟢 Easy AI — Makes mostly random moves with slight preference for better positions. Great for beginners!
- 🟡 Medium AI — Uses Minimax at depth 4 with position evaluation. A solid challenge for intermediate players.
- 🔴 Hard AI — Full depth-6 Minimax with Alpha-Beta pruning, corner prioritization, and mobility scoring. Very tough!
Reversi Strategy Tips
- ♟ Control the corners — Corner squares can never be flipped and anchor your territory.
- ⚠️ Avoid the danger zones — Squares next to corners (C-squares and X-squares) give your opponent easy access to corners.
- 📊 Fewer pieces early = better — Having fewer pieces in the early game means your opponent has fewer valid moves.
- 🔀 Maximize mobility — Keep as many valid moves as possible — it gives you more strategic options.
- 💡 Use the Hint button — When unsure, let the AI suggest the optimal move.
