One Key Resource (Seven Slots, Part 1)

Why our working memory is the most important resource we have in Chess.

Limitations are a key part of every intellectual, artistic, or athletic pursuit.

There’s only so hard you can throw a ball before you tear a muscle. There’s only so long you can paint in a day before the quality of your work diminishes. And there’s only so much you can write before your hands start to cramp up.

With training, we can extend some of these limits. Some people have managed to push these limits to almost superhuman lengths. But there’s always a limit somewhere.

When we think of limits in Chess, we know there’s a limit to our endurance in classical games. We sense the limit to how much knowledge we can take in before our brain gives up. Sometimes there’s a limit to how much frustration our emotional resilience will absorb before breaking.

In my research into Chess psychology over the past 3 years, I’ve realized there’s one limit lording over all others. Understanding, strengthening, protecting, and pushing it can have major effects on every part of our game.

It’s the limit of our working memory.

As a recap for people newer to this concept, our working memory is the function of our brain that holds information directly related to the tasks we’re completing at any one time.

As you read each word in this sentence, your working memory collects and holds all the context from the words you’ve already read. It allows the sentence, and this whole article, to make sense.

Without working memory, you would read each individual word and have no idea of how that word relates to any other word in the sentence. They may as well be random.

It’s your working memory that allows you to juggle a shopping list in your mind, do mental arithmetic, and keep track of the topic during a conversation.

Our working memory is not endless. It actually has a very small capacity. It’s designed to hold information only temporarily. Just long enough to let us complete whatever action we’re trying to complete. It rapidly takes things in and just as quickly lets them go again.

In 1956, psychologist George Miller defined the capacity of our working memory as having roughly 7 “slots”. Some people get 5 or 6, others 8 or 9. But most of us sit at 7, so that’s the number I’ll go with.


We can represent these slots on something like an audio meter, like you might find when recording or playing music. Each box represents one of our 7 slots, and the more slots we’re using at once the more effort it takes to hold.

7 slots isn’t a lot, especially if each slot can only hold one piece of information. So our brains prefer to take information in as “chunks”, connected segments of related information.

Here’s an example of how that works.

Take a second and memorize the number 4245737034.

It’s not easy. That’s a lot of random numbers. Your working memory is likely straining to hold it all.

Now try it again, but formatted like this: 424-573-7034

That’s the U.S. format for phone numbers.

If you’re a US resident, this format is so familiar to you that it should make the number instantly easier to remember. But even if you’re not in the US, I’ll bet you have an easier time with this format too.

You may even have naturally done something like this when you saw the number the first time.

Instead of each number individually taking a slot in our working memory, we have chunked them into 3 groups. And our brains can hold them more efficiently, using fewer slots.

Much easier.

But 7 slots is still not a lot of space, even if we chunk things together.

To make matters worse, our working memory doesn’t have exclusive claim over these slots.

It has to share space with several other mental functions.

If we need to think deeply, that takes slots. If we need to think creatively and make plans, that take slots. Withstand stress or pressure? Slots. Regulate our emotions? You guessed it, slots.

Now what game comes to mind when you think of information overload, deep thought, creativity, planning, stress, pressure, and a requirement for serious emotional regulation?


The game of Chess seems almost intentionally designed to put as much strain on our 7 slots as possible.

And when we run out of slots, things fall apart. We get tunnel vision and hang our queen. We lose emotional control and give in to tilt. We freeze in a complex position, with no mental space to think or make a plan.

But us humans are never bowed by a bit of mental challenge. Our brains are the most amazing, adaptable, powerful things in the natural world.

The fact we can play Chess at all is a stunning achievement for our species.

That’s the point on which I want to start this series. Appreciation for just how awesome our brains already are.

These 7 slots in our mind have so much work to do in a standard Chess game, and they do it amazingly well. Even if they do hang our queen every now and then.

Really stop and think about that for a second. Regardless of our skill or our rating, the fact that our brains have developed enough that something as complex as Chess is even possible is truly insane.

In our first series for 2024, we’re going to deep dive into this key mental Chess resource: our 7 slots.

We’ll explore all the ways we use them during a Chess game, what goes wrong when we run out of them, the things we can and can’t blame on them, and how we can train our minds to get the absolute most out of them.

I’ll see you next time with Part Two.

About the author

Aiden Rayner writes about how to make the adult brain better at Chess. Using science-backed insights, he works to change the narratives around adult improvement, and help adults discover the power of their Chess brains.

Related articles

Thanks for reading.

I hope you found it useful! If you did, would you please share it with another adult improver you know? You’ll be helping them and you’ll be helping me!

Share with #chesspunks

If you want to go deeper.

I collected all my key insights from 4 years of research about visualization and the adult Chess brain, and put them in a 5-day course that I’m giving away for free. Over 5,000 adult improvers are already making their brains better at Chess. Enter your email below and join us on the journey.


Scroll to Top