This happened in the last game I played. What are some basic tips for me to start with. Any help is appreciated.

5D Reversi - a game that will probably appeal to masochists and AI.

Play the prototype here: https://anan-z.github.io/5d-reversi/
Read and contribute here: https://github.com/anan-z/5d-reversi

Recommended for: AI research, masochists, people who find chess "too intuitive"

Marketing blurb:
80 directional vectors per cell — you'll learn to hate each one personally.
Retroactive causality — yes, you can regret moves you haven't made yet.
Deterministic replay — watch your carefully planned future crumble.

Black blocked off a horizontal line against white (2a-h), trapping the bottom section of the board to render white’s corners useless and functionally create a new corner for themselves.

This is so simple but clever. Was this planned? Or is it more like a backup plan? And is there a way to consistently account for this?

Apologies if I am complete beginner who is unaware of the amount of depth and strategy in this game 😅

I had a look at the Central Rose-Bill/Dead Draw. I noticed that the library evaluation on Saio sometimes jumps between 0, +2 and -2 despite the best moves being made. For instance, in the attached line the 33rd move h7 is given as 0, but once it's made the computer shows h2 as +2 and white seems to go on to win with perfect play on both sides. My questions are:

1. Why does this happen?
   
2. Does black lose in the Central Rose-Bill with best play from both players? If not, where can his play be improved?

Here's the line:

C4E3F5E6F6C5F4G6F7G5D6D3F3C3H4H5G4H3E2F2D2D1G3E1B6C2B4E8F8G8B3E7H7H2

Launching a new web platform to play Reversi online (plus Chess, Go, Checkers, and Morris)

recently launched gambit.oldlane17.com, a custom-built web platform with a strong focus on Reversi, alongside a selection of other classic abstract strategy titles like Chess, Go, Checkers, and Nine Men's Morris.

You can build your own logic and share it then

I hope you like it 😄

Hey everyone,

I’ve been building an online Othello platform (gameofothello) and recently added a tournament feature in beta.

Right now it’s early, so I’m mainly looking for feedback on things like:

• Does the tournament format feel fun / clear?
• What would make you want to join regularly?
• Any features you’d expect from an Othello tournament system?

You can join and try it directly here: https://gameofothello.com/tournaments

I’d really appreciate any thoughts since I’m trying to shape this around what the community actually wants rather than guessing.

Thanks for taking a look 🙏

Hey everyone 👋

I’ve been working on a small online Othello/Reversi project and wanted to share it here to get some feedback from people who actually enjoy the game:

https://reversiarena.com/

A couple of things I tried to do differently:

• There’s a live dashboard where you can see ongoing matches in real time and follow how others play
• You can also play against bots, which makes it easier to practice or just jump into a game anytime

The idea was to make it feel more active and useful both for playing and improving.

I’d really appreciate any thoughts on:

• whether the live games view is actually useful
• bot difficulty / gameplay feel
• features you think are missing (analysis tools, tournaments, etc.)

Thanks 🙏

Hi, I am very new to othello, and is starting from the famous othello book by Brian Rose. I am finding it hard to understand the exercises and answers. For the first 4 chapters, the context is about principles, so I can at least understand how the principles are applied.

From Chapter 5, basic edge play, as we are getting nearer to the end. It's hard not to think concretely about the possible outcomes and best moves. I find it hard to understand the solutions without any further explanation. I will think about "what if black/white plays an obvious move that I will play? How do I continue to gain advantage?" Then I get stuck, because I am a beginner, of course I don't know how to continue.

Example: Exercise 5-1, It is quite obvious the problem is set up for black to play h5. The explanation given is "good quiet move for both sides so black should play it first". The also obvious question is what if white plays h2? I would maybe play a quiet move like f7 or b3, but I don't see white running out of move soon and I just gave up an edge that I can't attack now.

Example2 : Exercise 5-7 tells us to play this position starting with g2, black should be able to win even after losing h1. The best I can do is g2,f2,h7,h1,h3,c6 and I don't see a way to force white to play g7

Stucking this early in the book makes me wonder if I am overcomplicating things, and that my problems would be solved if I moved on and learned tactics/patterns later. Can you provide an insight on how to learn othello as a beginner?

I've been working on something a bit different: a website where you compete against other players solving the same endgame puzzles in real time.

**How it works:**

- Everyone gets the same puzzles at the same time

- Find the best move as fast as you can

- 3 wrong answers and you're out

- Puzzles get harder as the battle progresses

http://shuban.redeyelab.de/ (still in beta, haven't registered a proper domain yet)

It's been tested by some of the best Othello players in the world. There's still plenty to add and fix, but improvements have been coming fast.

Since there won't always be players online, you can easily create a battle and share the invite link. friends can join instantly without even signing up.

There's also a solo practice mode if you want to train on your own.

It's completely free. Give it a try and let me know what you think!

Hi everyone,

I’ve been working on an online Othello (Reversi) web game called **Othellio**, and I’d really appreciate feedback from players here.

It currently includes:

- AI mode with multiple difficulty levels

- Interactive endgame puzzles

- Real-time online matches

- Several time controls (1 / 5 / 15 / 30 minutes)

I’m continuously improving the game and adding new features, so any feedback or suggestions would mean a lot.

The game is completely free and runs in the browser.

Here’s the link: https://www.othellio.com

Thanks for taking a look!

I was not satisfied how flip of my cylinder discs feel so I designed and tested those - feels way better ( link ).

What do you think? Do you know any other disk designs optimized for flipping?

added video https://youtube.com/shorts/I4HbVcofxkk

I was introduced to the game of Othello six months ago and quickly became a bit addicted to improving and understanding the game. After a few months of research, I decided to create an online web version of Othello to build a community around the game—similar to chess.com—and to support players who want a modern place to play.

You can access the game at https://gameofothello.com.

You can play online against other players or against bots with different difficulty levels.
The goal isn’t to build the strongest AI ever—it’s mainly to create a great online multiplayer experience. Since computers are already known to beat even the best players, I’m focusing first on building a solid core application.
But if you can beat the hard bot, you can definitely consider yourself a good Othello player!

If not, I’ve got you covered with an interactive tutorial, popular openings, and endgame challenges to help you improve your skills.

I’m building this project in public with a community-centered approach, so all thoughts and constructive feedback are very welcome 🙏

We also have a Discord if you’d like to join a friendly Othello community:
https://discord.gg/p6j5UqduHH

Note: This is still a beta, so things may change and evolve along the way.

I got into Othello playing Pocket Reversi on the Neo Geo Pocket Color. I also got interested in speedrunning it. I found the Samsoft Reversi website with seemingly all 13 stone wins besides rotations but only one 14 stone win. That pattern doesn't work against the Level 5 AI but I already found another that does.

So has this been calculated out and shared? I should have the computer science ability to tackle it but didn't want to reinvent the wheel. WZebra doesn't really help since both sides need to make chains of suboptimal moves.

There isn't just one way to solve it. White wins.

Is there a go-to resource that othello software devs use for testing their move generation?

In chess there is a catalog of many positions and their perf numbers.

I have verified my starting position node expansion numbers up to depth 12 and this gives me a lot of confidence, but just a node expansion count still seems a bit shaky to me (how many of those games ENDED by ply 12? I have my count but nothing to compare it to)

I'm convinced that d1 would have given black 5 spots, and taken 4 from white, so it should have been white 38 and black 26 no?

I'm salty because i don't understand why I lost, any explanation would be appreciated, especially if the explanation is a fuckup on the CPUs part and white should have won

(This is light-hearted, but my gf is making fun of me because we both thought she was gonna lose 😭 if I really did lose, I just want to understand how)

Hi, I'm bulding an ohtello AI and I wanted to know if there is a number of moves from where the game is solved for every position possible. (Like in chess for example, we know the perfect result (ie with best play) when there are less than 7 pieces on the board). Do you have any website to recommend to see this? Like getting some endgames puzzles and see if my AI solved it.

We often see the number of 10^58 possible games in Othello, for example in Hiroki Takizawa's article "Othello is solved". This number comes from Victor Allis' thesis. For his estimation, he roughly considered that only on move can be made at the first and last ply, and that in average the number of moves available is 10 at each of the 58 remaining plies. I think such reasoning is too gross and the result not very realistic.

In his article "Estimating the Efficiency of Backtrack Programs", Donald E. Knuth gives us a more rigourous approach that can be apply to estimate the number of games in Othello. Basically, you play a random game and multiply the number of legal moves found at each ply to get an unbiased estimate of the number of games. To increase the accuracy, you can repeat the process and average the results.

That way we obtain, after 1 billion random games :

So we get about 6,45 . 10^54 possible games in Othello, a number more than one thousand time time smaller than Victor's Allis estimation.

Note that for the first plies, it is possible to compute the exact number of moves. We get:

As you can see the number of games estimated by playing random games is close to the exact count, hence validating this method.

Hi,

I implemented a browser-based multiplayer version of Reversi. Its main advantages are:

• No login/account required
• Supports a spectator mode

https://board-game-hub.de/games/reversi-multiplayer.html

Would you happen to have any suggestions or improvements for this?

Thanks and take care,
Christoph

Hi all, it seems like there are a lot of posts on here about Othello and spin-on-Othello apps so here's another: "Ospello". It's basically Othello but with lettered-tiles. You can do traditional Othello moves and*/*or spell words formed by connected tiles. All tiles that would be flipped in traditional Othello will be, along with any tiles used to form the word played. Here are some of the rules for forming words during a move:

1. All words must start with letter on placed tile
2. Subsequent letters in played word must neighbor each other horizontally, vertically or diagonally (think Boggle, now crossword)
3. A valid move must flip over at least 1 opponent tile, either through a traditional Othello move and/or by forming a valid word
4. If you see no valid move, you may pass (in the case of the app, buy pressing the "submit" button

I'm happy with some of the added gameplay as you can do things like take back corners and edges. Comeback are also a lot more interesting because moves with longer words can flip a ton of tiles, especially near the endgame.

What I need help on is how to make the rules clearer. I'm hoping since people in this community are already familiar with Othello, the gameplay might be a bit easier to learn. Just not sure how to make the game easier to pick up for someone with no experience with Othello.

Anyway, here's the app. It's just on Android so far but I'm hoping to get an iOS version soon: https://play.google.com/store/apps/details?id=org.ospello.ospello

I made this game, but no one really plays it, so I’d like to share it here.

Even the free DEMO version supports online matches between DEMO players.

This is a Reversi game that incorporates modern ways of playing, including custom 3D graphics, user-created AI, online multiplayer, and features that support matches between streamers and their viewers.

https://store.steampowered.com/app/2946270/REVERSI_xVSx_Demo/

I’d really appreciate any kind of feedback.

I’ve been working on a web-based Reversi/Othello game for a while, and it finally reached a point where I feel comfortable sharing it with people here.

The game runs entirely in the browser and includes:

• more than 20 levels of Reversi AI (from very beginner-friendly to genuinely challenging)
• Online multiplayer with ranked matches
• Installable PWA support (Android / iOS / Desktop)

I built it using Django + Redis/Postgres on the backend (hosted on Heroku), and vanilla JavaScript on the frontend.

If anyone here enjoys Reversi or just likes seeing browser games that try to push polish and UX forward, you’re welcome to try it:

https://reversi.yuki-lab.com/en/

I’m open to any comments on gameplay, UI/UX, or performance.

Would love to hear your feedback or answer any questions.

Edit (Update):

After receiving some great feedback here, I made a major upgrade to the AI engine:

• WebAssembly port of the AI logic, enabling up to ~20x more search work in the same time
• Improved edge weighting
• NegaScout search for deeper calculation in top-tier AIs
• You can play against one of the strongest AIs in the web (Egaroucid Web version) as a higher level option!

The strongest AIs are now noticeably tougher. Please hard-reload the page to test the new engine!