Learn all you need about this website

On this page:

Who am I?

I am naturally an introverted person and I don't normally like to talk publicly about myself. But some users have expressed their concern about security. They have suggested that talking about myself would make them feel more comfortable. So here I am!!.

My name is Oscar Sotorrio. I am Spanish but I have lived in Malta and London for a few years. I have many hobbies in my life but chess and software development are my main passions. I am not especially great at any of them but linking these two passions, it is how playgrandmasters.com was created.

I don't have Facebook or Instagram. But I do have a Linkedin profile if you would like to check it out.


How can I contact the owner of this website?

Please, if you contact me I would appreciate if you would do it in a polite and respectful manner. You could send me an email to playgrandmasters[at]gmail.com or you could send me a direct message on my profile in Lichess.

What can I do if the website does not work for me?

If you encounter any issues while using the website it would be very much appreciated if you could report the problem by email: playgrandmasters[at]gmail.com. Please, do not use any other channels to report these problems, only by email. Thank you very much.

When you report a problem about the website, try to provide as much information as you can; describe step by step what happened, maybe take some screenshots to show me what was wrong, or even bettter a video with your phone.

Why did I create playgrandmasters.com?

After playing thousands of blitz games online I realised that I wasn't improving my chess skills. I decided to play more slow games but my schedule didn't allow me to play many classical chess tournaments. These are the reasons I created playgrandmasters.com; to be able to practise slow games any time it suits me. Playing through Grandmasters' games!.

What exactly is playgrandmasters.com?

You will be challenged with Grandmasters' games. During the game you will need to guess the best moves to solve the complications of the opening, middlegame and endgame, just like in a real game. After you finish, you get to review it and see the engine main line. What the video for more details.

How do I recommend you to use playgrandmasters.com?

Three easy steps to get the utmost from your training:

  1. Play the game with a real chess board like you would do in a tournament.
  2. Think deeply looking for candidate moves. Move the best candidate you find.
  3. When the game is over, review your training session with your coach, a chess mate or alone with an annotated book. Don't abuse of the chess engine.

What is EEP?

EEP stands for Estimated Elo Performance. To be honest it is a made up concept created exclusively for playgrandmasters.com. It is simply a number that tells you how well you did in a single game compared with other games. For instance, if you got 1900 EEP in a game, and in another game you got 1200 EEP, then you know in which game you performed better. EEP is not your real ELO.

EEP is not really important in terms of meaning. Sometimes you could get 2500 EEP in a single game and then in another game you could get 1500 EEP. Maybe one game had more forced moves, or the game was shorter, perhaps you had already played the game or the game might have been more in your style or opening knowledge.

How is EEP calculated? After analyzing thousands of Grandmasters games with Stockfish (depth 30), I realized that different Grandmasters agree with the engine in different percentages. Magnus Carlsen has a top 85% match with the engine in a single game. He is the player with the highest percentage matching the engine in a single game.

What I did was to take 85% as the maximum percentage that a human could agree with an engine in a single game. Also, Magnus Carlsen has the record of the highest ELO in chess history, 2882. Therefore, if you get 85% of the Grandmaster and/or Engine moves in a game, you would get an EEP of 2882. However, that does not mean your ELO is 2882.

How does ELO rating work in playgrandmasters.com?

The ELO in playgrandmasters.com does not try to replace any official ELO system. This ELO rating is the average of all your EEP scores achieved in every single game. The more games you play, the more accurate the ELO becomes.

What does it mean when I don't guess the right move?

For a given position, if you don't guess the Grandmaster or Engine's move it does not necessarily mean that you have made a bad move. It only means that there are two more better moves than the one you have done.

The way I see the training is as follows. When I make a move which does not match the Grandmaster's move, nor the Engine's move, then this is a "warning" to tell me that in this specific position I could improve my understanding.

Is there a chess engine running while I am playing a game?

No, there isn't. There is no chess engine running in the background and taking resources from your computer while you are playing the game. The games are analysed before they are uploaded to the system. There are several reasons why this is done. I will give you two reasons, which in my humble opinion, are the most significant.

First of all, the cost in terms of money. Computing time normally means more money to be paid. A game is analyzed once before it is uploaded instead of analyzing the same game over and over any time the user plays it.

Secondly, chess engines running on the browser of the user have limited strength. All the games in playgrandmasters.com are analyzed with depth 30, some of them depth 35. Only the main line of the chess engine is analyzed.

Some users have suggested that it would be nice to be able to guess not only the first engine's choice but also the second engine's move, and the third as well. While this is technically possible, it would not be viable at this point of the project because of the cost. The more lines to be analyzed, the more time and the more money.

Can I make a suggestion for the website?

Yes, you can. Your suggestions and opinions are always welcome. You could send me an email to playgrandmasters[at]gmail.com or you could send me a direct message on my profile in Lichess.

What happens when I make a suggestion? First, I will add your suggestion to the list of other users' suggestions as you can see in the following image.

User Suggestions

After that, I will prioritize which of these suggestions will be moved to my to do list. My time is limited; I have a job, I have a life and I can only work on this project during my free time. Therefore, with all due respect, I am the one who decides how I use my free time. I am the one who decides which suggestions get implemented first.

I made a nice suggestion long ago but It never got implemented, why? As I said before, all suggestions are welcome, but sometimes users make requests which would take months working on them. Maybe the request would increase the cost of the project in an unaffordable manner. Also some requests do not go in line with the philosophy of the website. Anyway, if you would like to know why your suggestion never got implemented I would be more than happy to explain it to you if you contact me.

How is playgrandmasters.com financed?

The website does not use annoying ads. I do not sell your personal data to marketing companies. At the moment, all costs associated with running servers, domains and so on, are coming from my own pocket. Yes, I am paying for everything. See below the bill for May 2020.

Billing May 2020

Is playgrandmasters.com free?

Yes, it is. You just need to register here and you can use all features for free without constraints of any kind.

Will playgrandmasters.com be always free?

I am going to be totally honest with you, I don't know. As you can imagine, running the website costs money. At the moment, I am personally paying for everything. The current cost of the website right now is close to the maximum I would pay to consider this as a hobby.

In any case my intention is for the website to remain free for everyone. Before forcing the users to pay, I will try to find other ways of financing the website like donations or sponsorship from a tech company.

None of the above has been decided yet. Everything depends on how the project evolves. The equation is simple, more users using the website, more money is needed.

How can I delete my account?

If you would like to delete your account, send me an email to playgrandmasters[at]gmail.com. You must send the email from the same email account you used to register in playgradmasters.com. Please, do not use any other channel to request for account to be deleted.

Allow me to apologize for the inconveniences of sending an email. At some point I would like to develop a user profile page where you would have total control of your account. In the meantime, I am really sorry!.

I am a tech guy, what is the tech stack behind playgrandmasters.com?

The website is hosted in AWS (Amazon Web Services). It has been developed using Cloud Serverless Technologies. The project is divided mainly in 3 individual projects: Frontend, Backend and BackOffice.

  • Frontend: Visual Studio Code, Bootstrap, Knockout.js, JQuery, Webpack, mocha.js, should.js, chai.js, sinon.js.
  • Backend: Visual Studio Code, AWS Serverless, S3, Cognito, API Gateway, Lambda with Node.js, DynamoDB, ClouldFront, Route 53.
  • Backoffice: Visual Studio 2019, .NET Core, SQL Server, XBehave, XUnit, NSubstitute, FluentMigrator.
  • CI/CD: I am using a private Github repository. I have 4 environments; LOCAL, DEV, TEST and PROD. To deploy I am using a weird mix between custom tools and manual actions. It is not ideal but I will improve it with time.