Chessbook vs Chessable: why I built a different way to study openings

By Marcus Buffett, co-founder of Chessbook.

I used Chessable for hundreds of hours. I accumulated about 1.5 million points and bought around 15 courses. Eventually, I became disillusioned with how I was spending my opening-study time. That frustration is what led me to build Chessbook.

The problem was that I could spend a lot of time getting better at remembering a course without feeling much better prepared for the games I actually played. I would keep forgetting a deep sideline, review it again, and wonder when I was ever going to get that position on the board.

If I had to reduce Chessbook to one idea, it would be this: opening study should not waste your time. It should save you time so that you can work on the rest of chess.

I think Chessbook is the better tool for building and maintaining your opening repertoire. Here's why.

Chessable wastes massive amounts of your time

When I go on Chessable right now, the first course I see on the opening browser is a 1.d4 repertoire for White. It has 781 trainable variations, 283 "Engine priority lines", 40 hours of video, and 140,000 words of instruction. The Odyssey is 120,000 words, for comparison. For part 1 and 2 together, the course is $600. It's my opinion that they're selling a massive waste of your time.

There's basically no limit to how effective studying tactics is for your chess. Opening study on the other hand, has very quickly diminishing returns. If your repertoire goes from nothing to 20 important and high-probability lines, then that will have a large impact on how consistent the positions you get are, how many traps you fall into, etc. The next 20 will be a smaller impact, the next 20 smaller still, and so on.

By the time you're getting to 1,500 lines, most of what you're learning is very unlikely to ever be seen in your games. So that being said:

How does Chessbook avoid wasting your time?

Find the gaps that matter at your level

The question I want my study tool to answer is: where is an opponent at my level likely to take me out of my preparation?

Chessbook looks for gaps using your saved moves, rating range and coverage goal. A gap is a position that needs a response. Estimated opponent-move frequencies help determine which gaps matter enough to prepare. An 800-rated player's repertoire shouldn't contain the same branches as a 2500-rated player's. How Chessbook measures completion

You choose how much preparation you want. A goal of “1 in 200 games,” for example, means preparing responses to positions estimated to occur at least that often along your repertoire. Start with a modest goal, fill those gaps, and deepen the repertoire when you have a reason to.

We even offer to trim imported repertoires to your coverage goal. If you bring in a huge collection of lines, the first useful thing to do may be to make it smaller. You can keep everything if you prefer.

Use a better review scheduling system

Chessable's default system moves through a ladder of review intervals: 4 hours, 1 day, 3 days, 1 week, 2 weeks, 1 month, 3 months and 6 months. Get the move wrong and it goes back to the beginning. Custom schedules are also available.

Chessbook uses FSRS to estimate how well you remember each move and when it needs another review. It uses your successes, mistakes and the time between reviews to update that estimate. We use custom weights fitted specifically to opening-training data, rather than relying on the generic defaults. Chessbook has recorded millions of opening reviews, and tens of thousands of people have practiced their repertoires here. That gives us a substantial source of real opening-training behavior to learn from.

On 7,000 held-out opening reviews, our custom-fitted FSRS model had about 8% lower prediction error than a simpler model using review level and elapsed time. It also predicted recall more accurately than generic FSRS weights. The point is to distinguish a move you're about to forget from one you already remember well, and spend your review time accordingly. That translates to benefits both ways: you're more likely to be prepared in your games, and less likely to study moves you already know well.

Count the practice you're doing anyway

Suppose you play three blitz games a day and follow your repertoire through your first eight moves in each. That's up to 24 opportunities to remember your opening moves. Why should you have to go back to a separate app to prove you know those lines? You've just played them.

When you connect Chess.com or Lichess, Chessbook processes your games and can record matching repertoire moves as successful reviews, updating their schedules. Remembering a move in a game provides useful evidence just as remembering it in a drill does. Chessbook's online-game integration

In an analysis of more than 150,000 recorded opening reviews, about 20% came from online games. That's practice you're doing anyway, being counted toward your repertoire training. About one fifth of the recorded practice happened without a separate Chessbook drill.

Flag repertoire mistakes in your games

You finish a game and wonder: “Did I follow my repertoire there?” If your preparation is spread across courses or files, checking this can be annoying, or you just assume you played your opening fine and don't check at all.

Chessbook compares your games with your repertoire and identifies where you played something different from your prepared response. You can go back to that position and work on it. A deviation doesn't automatically mean a bad chess move; it means you didn't play the response you had prepared. Chessbook's game feedback

That's the feedback loop I want: choose a response, practice it, try it in a game, and find out what needs attention. If you play on Lichess, we even have a custom integration with them that allows us to monitor your games live, so the second your game ends it can push a notification to you to let you know if you played your opening correctly.

Keep one repertoire you can change

Nobody gets all their openings from a single source. You might learn one from a book, another from a video and a third from your coach. What you want at the end is one repertoire that reflects the moves you've decided to play.

If you don't like a line in a course you've bought, you can't rewrite the original course. Chessable now lets you copy lines into a custom repertoire and edit those copies, but the purchased course remains the author's material. In Chessbook, changing your mind about a move is part of maintaining your repertoire, not maintained across 2 custom repertoires and 5 separate courses with selectively paused lines.

Your repertoire is yours, not a license from Chessable to view material

On Chessbook, you can edit the annotations on moves - because it's your repertoire. You can decide you don't like a line and go change it - because it's your repertoire. You can export your repertoire and use it somewhere else - because it's your repertoire. You get the idea.

When you buy a course on Chessable, you're buying access to its content under their terms. Their Terms explicitly say the content may be used only on Chessable and may not be exported out of it. That's a license to use their material on their platform under their terms, not a portable repertoire file you can take wherever you want.

That distinction matters to me. If Chessbook is providing value in how you study your repertoire then that's great and I want you to use the site. I want your repertoire to be yours though.

Yes, you can create a custom repertoire on Chessable and those they'll let you export, but that's not how 99% of people use the platform. We offer courses too, but if you use one as your repertoire we don't lock it down.

Where I still think a Chessable course is useful

Don't get me wrong, there is a ton of value in having an expert chess player explain lines and the ideas behind moves. There's just very little value in then memorizing thousands of moves over months. So if you want the former, Chessable is undoubtedly the best for that.

It's the long tail of opening study that Chessbook is built for, and in my opinion does a drastically better job. Less material to study and more effective systems to study it.

Take one opening you already play and put it into Chessbook. Set your rating and coverage goal, then look at the gaps. See whether it surfaces positions you recognize from your games and helps you decide what to prepare next.

Our ideal users

Chessable's ideal user purchases $hundreds worth of courses every year. I've been there, people I've known have been there. Thousands of lines to memorize, necessitating hours and hours per day of study.

My ideal user has a repertoire about a tenth of the size of a standard Chessable course, built for their level. They come study their moves 5 minutes a day, then spend the hours they save on everything else that makes chess so hard to learn.

Frequently asked questions

What is the main difference between Chessbook and Chessable, for opening prep?

Chessable is centered on buying courses, Chessbook is centered on making the most of your limited time to study openings and about having one place to store your own repertoire, not to look at someone else's.

Why use Chessbook if I already own Chessable courses?

Chessbook can help you decide which positions still need preparation and maintain the responses you intend to play. Owning a course gives you material to learn from; Chessbook's coverage goal allows you to determine the small fraction of that course you should actually memorize for your games.

Is Chessbook suitable for beginners?

My recommendation for beginners is to start small: prepare common replies and expand when your games give you a reason. Chessbook lets you choose a rating range and coverage goal, and start from a pre-made repertoire or Autofill. You don't need to begin by memorizing a large course. Pre-made repertoires, Autofill

Does Chessbook choose moves for me?

You can choose your moves one-by-one fully manually if you want, or you can import an existing repertoire, or you can ask Chessbook to create a repertoire tuned to your style and level, or you can use one of our pre-made courses. All are valid ways to get started with Chessbook.

Will Autofill replace moves I already saved?

No. Chessbook's Autofill protects every move saved before the build, whatever its source. That includes manually chosen moves, imported moves and moves saved from earlier Autofill runs. A deeper build extends that input rather than replacing the responses you may already have learned. Autofill documentation

Is Autofill better than building a repertoire manually?

Chessbook's Autofill beats virtually any human at creating opening repertoires. We've run the numbers comparing Autofill's built repertoires versus the tens of thousands of hand-built repertoires on our platform, and it's not close. The benefit of building your own repertoire is that the act of choosing the lines is a powerful tool for remembering what you play initially. How Autofill works

What is an opening repertoire gap?

In Chessbook, a gap is a position where your repertoire needs a prepared response. Estimated frequency and your coverage goal help determine which gaps to work on. Closing a gap means choosing a response; learning to remember that response is a separate step. We calculate this by importing billions of games from Lichess. Completion documentation

What does a “1 in 200 games” coverage goal mean?

Chessbook's 1-in-200 goal means preparing responses to individual positions estimated to occur at least that often along your repertoire. It does not mean you will stay in preparation for 199 out of every 200 games. Frequencies are estimates, and many individually rare alternatives can collectively occur often. Coverage explained

Can Chessbook make an imported repertoire smaller?

Yes. Chessbook offers to trim imported material to your coverage goal, removing rare lines beyond that target. The import flow also lets you keep everything. Trimming is useful when a large imported repertoire contains more preparation than you currently want to maintain.

What spaced-repetition algorithm does Chessbook use?

Chessbook uses FSRS to update a model of memory from review results and elapsed time, then calculate the next review interval. Its aim is to schedule practice according to how you remember each move. Chessbook scheduling

Does Chessbook demonstrably require fewer reviews than Chessable?

The analysis here supports more accurate recall predictions: on 7,000 held-out opening reviews, Chessbook's custom-fitted FSRS model had about 8% lower log-loss prediction error than a review-level-and-elapsed-time baseline. Chessbook also credits remembered moves in online games toward your review schedule. Chessbook scheduling

Do Chess.com and Lichess games count toward Chessbook reviews?

Yes. When Chessbook processes connected online games, matching repertoire moves can be recorded as successful reviews and update their schedules. Game credit is subject to the app's processing and deduplication rules; it is not a promise that every repeated move in every game creates a separate review event. Chessbook game integration

Can Chessbook tell me whether I followed my repertoire?

Yes. Chessbook compares connected online games with your saved repertoire and identifies deviations from your prepared responses. A repertoire deviation is not automatically an engine mistake: a different move can be sound while still differing from what you intended to play. Chessbook game feedback

What if I play a good move that isn't my repertoire move?

Chessbook distinguishes move quality from repertoire recall. A sound alternative can be a soft fail if your repertoire continues from the position: the move is acceptable chess, but you didn't recall your prepared response. At the end of your repertoire, a sound alternative gets no scheduling penalty. Add the alternative to your repertoire if you want to train it as a chosen response. Soft-fail rules

Is Chessbook free, and what does Pro add?

Chessbook has a free Starter plan with a move allowance of 100 moves per side. We find that this is enough for 90% of our active users. Many users use Chessbook for years without realizing there's a Pro tier. Pro removes the move limit. Check the current web offer and the applicable app-store price if you subscribe on mobile. Chessbook plans

Is this an unbiased comparison?

Absolutely not. This article is written by me, Marcus Buffett, co-founder of Chessbook, and collects all the questions I've received about why someone would use Chessbook over Chessable, into one article.