Chinese Spaced Repetition App

Spaced repetition is a technique for spacing out reviews according to their difficulty. It does this by leveraging the science of memory and forgetting to schedule optimal review times.

HanziHero is a Chinese character learning application that leverages spaced repetition and mnemonics to make learning Chinese characters as easy and efficient as possible.

Let’s go into depth about what spaced repetition is and how HanziHero leverages it to help you learn Chinese characters.

What is spaced repetition?

Spaced repetition is a technique for spacing out flashcard reviews according to their difficulty. Items to review that are more difficult and frequently forgotten or gotten wrong will be shown more frequently. Conversely, items that are easy will be shown less frequently. By arranging reviews in this manner, the student can reduce their study time drastically while retaining the same information.

A spaced repetition system does this by leveraging two pieces of information. The first is something known as a forgetting curve, which models the speed we forget things at. The second is how many times you answered something correctly or incorrectly.

Forgetting curve

When we learn something for the first time, we often quickly forget it. However, the more times we are introduced to the same thing, the more likely we are to remember it. Our brain slowly prunes information it does not seem to need, and knows that something that comes up more often is more useful, and will keep it around.

For example, it is usually not till the second or third time we hear someone’s name that we will finally remember it.

This phenomenon is known as the forgetting curve, and it can be illustrated by the graph below.

forgetting curve

Each of the curves show the strength of the same memory over time. If it is only remembered once (the leftmost curve), the strength of the memory fades quite quickly. However, if one consciously remembers that same memory each day, by the third day the memory is much stronger, and fades at a much slower rate.

If we are constantly forgetting something, it may be because our initial memory is weak to begin with. Such as forgetting a math formula that we never quite fully understood. However, it is also often due to us not remembering or reviewing it a sufficient number of times. The forgetting curve models these two aspects into one graph or formula, which can in turn be approximated by an algorithm.


Knowing what the forgetting curve is and how it works, the key becomes to try to find an algorithm that can approximate it. If we can review an item right before we are about to forget it, we can keep it in memory while also additionally ensuring that it will fade at a slower rate going forward.

There are many algorithms that do this. Popular spaced repetition software like Anki uses an algorithm called SM-2. HanziHero itself uses a simpler, but just as effective, algorithm called the Leitner system.

These algorithms work by taking into account how many times you got a review item correct or wrong recently, in addition to how many times you have reviewed it already to approximate that forgetting curve mentioned above.

A spaced repetition algorithm will show items that you tend to get incorrect more often, as it knows your memory of it is weaker. Similarly, it will not show items you just reviewed, as those memories tend to be stronger. In short, a good spaced repetition algorithm will show you an item right before you may forget it.

How spaced repetition helps you learn Chinese characters

To reach literacy in Chinese, you must learn over 3,000 characters. In our opinion, this is by far the hardest part about learning Chinese, which is why we’ve dedicated ourselves to trying to make it easier for all.

It is not feasible to review all 3,000 characters each and every day, so the use of spaced repetition is more or less required for learning Chinese characters. Let’s go into how it helps.

Less time reviewing, more time learning and using

If you spend all of your time reviewing the characters you have already learned, you will have no time to learn new characters! Spaced repetition cuts down on review time, allowing you to spend more time learning new characters.

The end goal, as with all language learning, is to get good enough that you can spend most of your time actually using the language instead of just memorizing characters. We think that spaced repetition serves this goal well by minimizing review time so you can spend your time on the more interesting and rewarding parts of Chinese.

HanziHero leverages spaced repetition to keep review time down and manageable. Most users will not need to review the characters, words, and components they studied more than a small amount of time each day.

Keeps track of weak points

Every spaced repetition algorithm keeps track of review history, and most of them surface that information for you to review. By having review history, you can look through the items you get wrong the most to determine which things you may need to study again, or find a new way to remember.

HanziHero surfaces this information for each character we teach. You can look up any character you learned and find a full review history for that item.

Try HanziHero’s spaced repetition system

Spaced repetition is a powerful technique for learning languages, and is indispensable for learning a language as hard as Chinese!

HanziHero utilizes spaced repetition, along with an optimum character learning order and mnemonics to make learning Chinese characters as painless as possible. We have a generous free tier that you can try anytime, no credit card required!

Ready to use spaced repetition to learn (and remember!) Chinese characters? Create an account and give it a try!