The standard tools for serious Reversi study are Edax (the strongest free open-source engine), Saio and WZebra (established analysis programs used by competitive players), and eOthello (an online platform with game databases and competitive play). Together these tools cover everything from opening preparation to endgame solving to game review. This guide explains what each does and how to use them effectively.
Why Use Software for Reversi Study?
Reversi occupies a unique position among board games: computers have played superhuman Reversi since 1997, but the game has not been fully solved. This means computer programs are simultaneously:
- Stronger than any human — providing an authoritative “best move” for any position
- Trainable tools — analysis reveals what you did wrong and why the computer’s move is better
- Not oracles — at very high depth, the game is still open; the computer gives strong evaluations but not perfect truth
Using software for Reversi study is analogous to a chess player using Stockfish: you gain access to near-perfect tactical and strategic assessment, which dramatically accelerates improvement.
Edax: The Gold Standard
Edax is the strongest freely available Reversi engine. Developed by Richard Delorme, it is open-source (available on GitHub) and has been refined to a very high level.
What Edax Can Do
Position analysis: Given any legal board position, Edax evaluates all legal moves and ranks them by score. Positive scores favour the player to move; negative scores favour the opponent.
Best move identification: Edax shows which move it considers best and by how much it leads the alternatives. This is the core feature for game analysis — finding where you diverged from optimal play.
Principal variation: After showing the best move, Edax can display the principal variation — the sequence of moves it expects both players to make from that position. This shows the strategic plan the best move sets in motion.
Endgame solving: From approximately 20 empty squares, Edax can solve positions exactly — computing the perfect outcome with optimal play from both sides. This is invaluable for endgame training.
Depth control: You can set how many moves ahead Edax searches. Higher depth gives more accurate evaluations but takes longer. For casual analysis, medium depth is fast and sufficient. For opening preparation or complex positions, deep analysis reveals subtler truths.
Getting Edax
Edax is available at its GitHub repository (search “Edax Reversi”). Precompiled binaries exist for Windows; Mac and Linux users can compile from source. The interface is command-line based, which can feel unfamiliar at first but becomes natural quickly.
Some third-party GUI frontends for Edax are available that provide a graphical board interface.
How to Use Edax for Game Analysis
- Record your game moves in standard notation (see the notation guide)
- Input the moves into Edax to replay the game position
- At each move, check Edax’s evaluation: if your actual move was rated significantly worse than the best move, that’s a mistake worth studying
- For each identified mistake, ask Edax for the principal variation — what the game should have looked like with optimal play
- Understand why the better move is better (corner access? mobility? stability?) before moving on
WZebra: The Classic Analysis Tool
WZebra (part of the Zebra family of programs) was for many years the most widely used Reversi analysis tool in the Western competitive community. It provides a graphical board interface alongside strong engine analysis.
What WZebra Offers
Graphical interface: Unlike Edax’s command-line setup, WZebra provides a visual board where you can click to make moves and see analysis overlaid.
Move evaluation display: WZebra shows the evaluation score for each legal move overlaid on the board squares, making it easy to see which moves are good and which are poor.
Game replay and analysis: Import a game record and replay it with evaluations shown at each step.
Opening book: WZebra includes an opening book — a database of analysed opening positions — which is useful for opening preparation.
Endgame solver: Like Edax, WZebra solves endgame positions exactly from a sufficient depth.
Availability
WZebra is a Windows application. It may be available via emulation on Mac and Linux. The program has not been actively developed in recent years, but remains a useful and trusted tool. Search for “WZebra Reversi” to find download sources.
Saio: The Japanese Standard
Saio is a strong Reversi engine widely used in Japan’s competitive community, which is the world’s largest and most developed Othello scene. Saio is less well known internationally but is a standard tool for preparation among Japanese tournament players.
Saio provides similar analytical capabilities to Edax and WZebra — position evaluation, endgame solving, and opening analysis. If you are engaging with Japanese competitive resources or studying Japanese competitive games, Saio familiarity is useful.
eOthello: Online Play and Game Databases
eOthello.net is an online platform serving multiple purposes for the competitive community. It is used by players affiliated with national federations recognised by the World Othello Federation and serves as a bridge between online and official competitive play:
Competitive online play: Rated games against real opponents from around the world. The rating system gives you a numerical measure of your strength and matches you with appropriate opponents.
Game database: eOthello archives competitive game records. You can search for games by player, opening, or position. Studying how strong players handled specific opening lines or endgame structures is one of the most effective training methods.
Player profiles and ratings: Track your own rating over time and compare with other players.
Community: eOthello connects players across the global competitive community. Many national federations use it as a platform for their members.
Using Software Effectively: A Study Workflow
For Opening Preparation
- Choose 2–3 openings you want to play with each colour
- Load the opening into your analysis program
- Play out each line 10–12 moves and check the computer’s evaluation at each step
- Identify “critical junctures” — positions where one move is significantly better than alternatives
- Memorise the best responses at critical junctures in your chosen lines
- Practice the openings against AI opponents on platforms like Reversi Pro or eOthello
For Endgame Training
- Set up positions with 15–20 empty squares (find these in game databases or create them)
- Try to solve the position by hand — who wins with perfect play, and by how many discs?
- After solving (or giving up), check with your analysis program
- Compare your solution to the computer’s: did you find the right moves? The right sequence?
- If you were wrong, replay the position and trace exactly where your calculation diverged
Even 20–30 endgame drills significantly improve calculation speed and accuracy.
For Game Review
After a loss (or a close win), the review workflow:
- Record or recall the move sequence using Reversi game notation
- Input into Edax or WZebra
- Walk through the game looking for positions where you chose a move rated worse than the best alternative by more than 4–5 centidiscs
- For each significant mistake, understand the correct move and why it’s better
- Check whether the same type of mistake appears in multiple games — pattern mistakes are the highest-leverage targets for improvement
Online and Browser-Based Analysis
For players who don’t want to install desktop software, several options exist:
Reversi Pro: Includes an AI engine accessible directly in the browser. While not designed as a research-grade analysis tool, it provides immediate feedback on game quality at adjustable AI levels and is available without any installation.
Web-based Othello analysis tools: Several websites provide browser-based position analysis using JavaScript engines. These are less powerful than Edax or WZebra but accessible to anyone without software installation.
Choosing the Right Tool for Your Level
| Player Level | Recommended Tool | Purpose |
|---|---|---|
| Beginner | Reversi Pro AI | Play and improve without analysis complexity |
| Intermediate | WZebra or Edax + visual interface | Start reviewing your own games |
| Advanced | Edax (command line, deep search) | Opening preparation, endgame research |
| Competitive | Edax + eOthello + Saio | Full preparation suite with database access |
The most important thing is to start using any form of computer analysis — even a simple AI opponent at a high difficulty level gives you feedback that purely human-only play cannot. The earlier you incorporate software into your study, the faster you improve. For the full improvement roadmap, see how to get better at Reversi.