Anki and the Magic of Spaced Repetition

Learning never exhausts the mind.

Leonardo da Vinci

Preface: What is Anki?

Anki is a multi-platform electronic flashcard program based on the principles of active recall and spaced repetition. Its name comes from the Japanese word for “memorization.”

As opposed to reviewing flashcards conventionally by sorting through an entire desk continuously, in Anki you review only a fraction of your total deck, focusing on the material most on the verge of being forgotten.

That is, material with which you are more comfortable is seen at longer time intervals compared to material that is more difficult, which is “due” more frequently. As a result, less of your time is wasted reviewing information that can be more easily recalled. 

Therefore, one only reviews what is necessary, separating the wheat from the chaff, making learning more efficient as well as increasing the retention of important material.

(Some readers may also be interested in my advanced guide for Anki.)

Preface: How Does Anki Work?

The spaced repetition algorithm on which the software is based feeds off of data input by the user as they rate the “difficulty” of each card after its review.

For example, after reviewing this new card, the learner rates the difficulty of the card before moving onto the following new card.

The respective time intervals at which I would next see the card are listed above each difficulty option:

  • Less than 1 minute if I couldn’t recall the information (“Again”);
  • Less than 10 minutes if I had difficulty recalling the information (“Hard”);
  • 1 day if I could recall the information with ease (“Good”);
  • 4 days if I knew the answer instantly without much recollection needed (“Easy”)

Note that as cards transition from “New” to “Learned,” these time intervals become progressively longer and longer, provided that there is higher retention of the material. 

The instructions I provide below are designed to function as a quick start guide, allowing users to begin understanding and using Anki to its fullest potential.

Familiarizing yourself with the software should take about 30 minutes and does not have to be completed all at once.

For those looking for other ways to accelerate their learning even further with Anki, an advanced guide is forthcoming.


Part 1) Getting Started

Step I: download Anki for free.

Upon opening Anki for the first time, you should create a profile at Ankiweb to ensure your decks are saved and can be used on other platforms (iPhone, Android, etc.).

In the 2.1 version, click on the “Sync” option listed in the top toolbar. In older versions, the sync button is found in the top right corner of the window with two arrows forming a circle.

Once you select “Sync,” another screen will prompt you to create an account.

You can also create a profile, which can be useful if you want to review material from different semesters or areas of focus. Otherwise, you can skip it.

Before starting to create and review cards, performing some minor formatting adjustments will ensure that once you begin to enter information, the process is as seamless as possible.

Click the “Create Deck” button on the bottom of the screen to start. Name your deck as you see fit. If you’re studying for the MCAT, for instance, you might want to name your deck, “Chem/Phys,” or the like.

Next, click “Add” at the top of the screen to add cards to the deck. Next to “Type,” you will see a white box that reads “Basic.” Click that box or use the shortcut Command/Cntl + N to see the different Card Types.

Screen Shot 2018-06-09 at 17.59.08
Screen Shot 2018-06-09 at 17.59.57

The main two types of cards you’ll likely be using are Basic and Cloze.

Whereas Basic cards are self-explanatory (they simply have FRONT and BACK fields, like a physical flashcard), Cloze cards include a special feature that allows you to delete a section of your card (called a ‘Cloze deletion’) in order to have that missing word or phrase serve as the ‘answer’ to the card.

See the below image for an example. The card reads, “The pineal gland secretes […]

Once the answer is revealed (melatonin), I then proceed to rate the difficulty of the card (more information below).

Screen Shot 2018-06-09 at 18.02.25

I renamed each of these card types “1. Basic” and “2. Cloze” so that when I am creating cards and want to quickly switch card types, I can simply type “1” or “2” and then press enter to change the type.

To change the names of these card types, click “Manage” and then “Rename” on the appropriate card type.

See Shortcuts below for how to quickly swift between card types.

Screen Shot 2018-06-09 at 18.08.59.png

Part 2) Creating Good Cards

A (Slight) Tangent

The creation of good cards is undoubtedly the single most important part to using Anki effectively. Without clear, concise cards, you’re better off wasting your time with physical flashcards.

Dr. Piotr Wozniak, who created the algorithm that Anki uses, published a comprehensive overview of how best to construct electronic flashcards, entitled 20 Rules of Formulating Knowledge. (Dr. Wozniak is a peculiar fellow— read this Wired article to learn more.)

I highly suggest you read Wozniak’s 20 rules, though it will take about 20-30 minutes to complete.

If you’re pressed for time, I’ve summarized what I think are the most important rules: #1, #4, and #5. I also give examples of how to apply these rules below.

Rule #1) Understand First. Then Learn

Simply put, comprehension of information must precede any attempt at learning. If you are a non-Francophone, cramming a chapter of a history textbook in French is utterly futile. Surely it would be possible to memorize a few sentences, but you would know nothing of French history.

Students will commonly commit certain processes to memory–the TCA cycle, for example–without giving thought to their underlying mechanisms or their relationship to higher-level topics.

You must first understand the broader role of the TCA cycle in producing ATP from glucose before committing any specific enzymes to memory.

Rule #4) Minimum Information Principle

Make material you want to learn as simple as possible. Simpler models are easier to create, learn, and memorize.

Simplicity is the ultimate sophistication

Leonardo da Vinci

Simple is easier to remember. Remembering an idea is akin to running through a labyrinth—it’s easier when your brain knows exactly which way to go. The labyrinth in your mind is easier to navigate when the idea is simpler.

Moreover, simple items also make the scheduling of repetitions within Anki easier.

In general, the longer it takes to remember an idea, the simpler it needs to be. Answers, in particular, should be as short as possible.

Rule #5) Cloze Deletions (denoted as […])

Cloze deletions are a quick and effective method of converting textbook knowledge into knowledge that can be learned through spaced repetition. As explained in Part 1), they are simply words deleted from a sentence.

In college, I introduced a friend who was studying cognitive psychology to Anki.

This was one of her physical flashcards on Brain Plasticity:

Front: Brain Plasticity


  • Organizational flexibility- allows us to recover from injuries and other deficits
  • Children born with brain lesions, other regions will take over the functions that would have been performed in that damaged area
  • Occipital lobe is active when visually impaired people read braille
  • Neurogenesis- brain cells grow new connections allowing for plasticity in nervous system
  • As I hope you’ll note, this card is in direction violation of Rule #4, the Minimum Information Principle. This single card can be, and should be, broken up into at least six other cards:

As I hope you’ll note, this card is in direct violation of Rule #4, 

Card 1)

Q: What allows for recovery from injuries and other deficits that affect the brain?

A: Organizational flexibility

Card 2)

Q: What is the adaptive significance of organizational flexibility?

A: Helps us recover from injuries and other deficits that affect the brain.

Card 3)

Q: The […] lobe is active when visually impaired people read braille

A: Occipital

Card 4)

Q: What is the core principle of brain plasticity?

A: Other regions take over functions that would’ve been performed by lesioned area

Card 5)

Q: […] is the process in which brain cells grow new connections

A: Neurogenesis

Card 6)

Q: Neurogenesis is the process in which […] grow new connections

A: Brain cells

As Dr. Wozniak put it best,

“We want a minimum amount of information to be retrieved from memory in a single repetition! We want answer to be as short as imaginably possible!

Piotr Wozniak

Creating Good Cards

Creating Basic cards is pretty straightforward—simply type into the Front and Back fields and press “Add.”

For Cloze cards, switch the card type to “2. Cloze” and then highlight the word or phrase to be deleted. Then, click the “[…]” button next to the paperclip on the toolbar or press Command/Cntl + Shift + C.

Refer to the images below:

Screen Shot 2018-06-09 at 18.18.03
Screen Shot 2018-06-09 at 18.19.24

Note that I also bold vocabulary terms. This is a personal preference and serves to help those terms stand out from the card and hopefully trigger the memory.

Also note that Cards 5 and 6 in the above example can conceivably be combined into one card.

When entering each of these cloze deletions, you would select ‘Neurogenesis’ and ‘brain cells’ and ensure they are given different c# numbers. Such as, “c1” and “c2.”

You can also delete separate words from a card as well if both cloze deletions have the same code, such as c1. For instance,

Screen Shot 2018-06-09 at 18.23.24.png

Note that a hint for each cloze deletion can be provided by including “::hint” after the deletion. In the above image, the card would display as “[structure] in the […] lobe is active during speech production.”

Finally, upon creating decks, you have the option to create ‘stacked’ decks when the subject matter can be separated into different topics or chapter.

Note that with a large amount of stacked decks, Anki will begin to run more slowly. A workaround to stacked decks are tags. For instance, I would tag all of the vocab words from Chapter 8 in my Spanish course, “Capítulo 8” instead of creating its own specific deck.

As you’ll learn in Part 3), you can also study specific tags within a deck if they’re more pertinent at a certain time.

Part 3) Studying

Clicking on one of the decks will bring up an overview of its contents.

Clicking “Study Now” will begin your study session. In this Natural Science deck, for instance, I will be learning 18 new cards and reviewing 88 old cards.

In the “Learning” stage, new cards are presented several times until Anki believes you have learned it—by default this is when you answer the card correctly at least twice.

A learned card then sits in the “Reviewing” stage during which there will be progressively longer and longer time intervals between reviews.

If at any point you get the wrong answer (called a “lapse”), a card then reverts to “learning” stage again.

While this may feel discouraging, don’t kid yourself; if you don’t know an answer, you’re better off reviewing the card from the start than pretending you knew the answer all along.

Upon answering a new card (the spacebar can be pressed in order to show the answer), buttons appear at the bottom of the screen for you to evaluate your performance, as first shown above.

Next to creating effective cards, selecting the right level of difficulty is the second-most crucial part in using Anki. The ease you select will determine the interval in which the card is next shown to you. (These intervals can be seen right above the buttons, with ‘m’ referring to minutes, ‘d’ referring to days, and later, ‘mo’ referring to months.)

I highly recommend NOT studying cards on the same day you create them. Because you just reviewed the material, you will be far more inclined to hit ‘easy’ when reviewing, which may unintentionally decrease your long-term retention of that material.

Beyond the default study session, there is also a Custom Study feature, which can be found at the bottom of the Deck screen.

One of the most useful features I’ve found is the “cram mode,” which is located under “Study by card state or tag” or “Custom Study” option on the bottom toolbar. As the image below shows, the cram mode will show all cards in the deck in random order. I find this especially helpful right before exams.

Screen Shot 2018-06-09 at 18.29.14

Part 4) Shortcuts

As I alluded to above, there are a plethora of add-ons that greatly enhance the experience of Anki.


  • “b” from the deck overview screen opens Browse
  • “a” from the deck overview screen opens Add (new cards)
    • Command/ctrl + D to change the Deck
    • Command/ctrl +  N to change the card Type
      • If you’ve also added “1,” “2,” etc. to the name of your card types, you can easily type # and then press enter to quickly switch
    • Command/ctrl + Shift + C will add a Cloze deletion to a highlighted word/phrase (saves time from having to click on the button on the toolbar)
    • Command/ctrl + Enter to save/add the card

When reviewing a card,


Part 5) Closing

Anki and the principle of spaced repetition will only work if you commit to studying every single day. If you take off a few days, a mistake I have made in the past, you will end up having to sift through hundreds of cards in one sitting. Not fun.

Studying every day, meanwhile, will ensure you only deal with a manageable amount of cards. During my first ten weeks with Anki, I spent an average of 20 minutes a day studying. That’s all it has taken for Anki to be effective. 20 minutes a day. Provided that your cards are ‘simple’ enough, it should take you about 15 minutes to study 100 cards.

Rest assured that taking off a single day won’t significantly increase your workload, though the next day you review, there will certainly be more cards to study.

Other Guides:

Happy Learning!


1 thought on “Anki and the Magic of Spaced Repetition”

  1. I’m trying to figure out how I missed this truly very informative blog. Came following link from recent ‘Building a …’ blog. So much to learn, so much to know. Thank you.

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