Spaced repetition: how Japanese finally sticks in your memory

You learn twenty new words, and by the next day fifteen are gone. Sound familiar? That is not a sign of a bad memory, it is simply how your brain normally works. The good news: there is a method that outsmarts exactly this forgetting, and for Japanese with its thousands of vocabulary words and kanji it matters more than for any other language. It is called spaced repetition, and this is how it works.

The forgetting curve: your brain tidies up

Back in the late 19th century, the psychologist Hermann Ebbinghaus measured how quickly we forget what we learn. His result, the famous forgetting curve, is sobering: without review, about half is gone after a day and most of it after a week. This is not a malfunction. Your brain constantly deletes information it considers unimportant to make room for what matters. A Japanese word you have seen exactly once falls squarely into that category.

The trick: every time you recall something just before forgetting it, you tell your brain "this one matters". The forgetting curve flattens, the memory lasts longer. After a few of these rescue missions, the word settles into long term memory and needs hardly any maintenance.

Growing intervals: the principle

Spaced repetition is built on exactly this: reviews at growing intervals, always just before you would forget. A typical rhythm looks like this: first review after one day, then after three days, then a week, then a month. If you know a word confidently, the gap keeps growing. If you slip, the interval starts small again. A spaced repetition system like Anki, WaniKani or the Sakuraflow vocabulary trainer calculates these dates automatically for every single card. You only have to do one thing: go through the due cards every day.

The three typical mistakes

Spaced repetition is simple, but there are three mistakes learners reliably use to break the system for themselves. All three are avoidable.

• 🌸Too many new cards per day: every new card creates future reviews. Start 50 new words a day and three weeks later you are staring at 300 due reviews and give up. 10 to 20 new cards a day is completely sufficient.
• 🌸Isolated words instead of example sentences: a card that just says "行く = to go" stays abstract. With a short example sentence like 学校に行く you learn the word together with its particle and context, and it sticks far better.
• 🌸Postponing reviews: the algorithm only works if you see cards when they are due. Three days off means a mountain that kills motivation. Ten minutes every day beats one hour once a week.

A routine you can actually sustain

The best system is the one you do not abandon. This routine costs around 20 minutes a day and fits into any schedule.

1. 1Morning, 10 minutes: clear all due reviews, for example over coffee or on the train. Reviews always take priority over new material.
2. 2Evening, 10 minutes: add or unlock 10 to 20 new words, ideally ones you met that day in texts, shows or lessons.
3. 3Once a week, tidy up briefly: cards you keep failing get a better example sentence or a mnemonic.

Nothing more is needed. At 15 new words a day, that adds up to over 5,000 words a year, enough to jump several JLPT levels. Not because you study harder than everyone else, but because nothing gets lost anymore.

Frequently asked questions

Forgetting is not a weakness, it is a setting in your brain that you can reprogram. Set up a spaced repetition system today, start with ten words and let the intervals do the work. A month from now you will be surprised how much just sticks.