Remember what you study
Spaced repetition schedules reviews at increasing intervals so that material returns to you just as it starts to slip away. This page gives you a working routine: a box layout with real intervals, an ordered daily procedure, and the history of the method from Ebbinghaus to SuperMemo.
| Box | Reviewed | Correct answer | Wrong answer |
|---|---|---|---|
| Box 1 | Most often — daily | Advances to Box 2 | Stays in Box 1 |
| Box 2 | Less often than Box 1 | Advances to Box 3 | Returns to Box 1 |
| Box 3 | Less often than Box 2 | Advances to Box 4 | Returns to Box 1 |
| Box 4 | Less often than Box 3 | Advances to Box 5 | Returns to Box 1 |
| Box 5 | Least often | Stays in Box 5 | Returns to Box 1 |
| New cards | Added in small batches | Enter Box 1 | Enter Box 1 |
It schedules reviews at increasing intervals so that you see material again just before you would forget it.
Ebbinghaus created the forgetting curve, a graph portraying the loss of learned information over time, and postulated that it can be curbed by reviewing material at increasing intervals. Every time you review, the curve flattens: the next gap before the material slips away becomes longer.
In practice this means a card you answer correctly today is not shown again tomorrow but pushed to a later box, while a card you answer wrongly comes back to the first box and is seen again soon.
The technique is deliberately simple. You do not need software: a stack of cards sorted into boxes with increasing review intervals is enough to run the system.
Cards are sorted into groups reviewed at increasing intervals; the first box is reviewed most often.
The Leitner system is a simple implementation of spaced repetition where flashcards are sorted into groups reviewed at increasing intervals. Each box has its own review frequency, and a card's box determines when you will see it next.
The rule that drives the whole system is one-way movement on success and a reset on failure: correctly answered cards advance to the next, less frequent box, while incorrectly answered cards return to the first box.
Because wrongly answered cards return to the most frequent review box, difficult material is seen more often. The layout below is the table to set up before your first session.
Follow the steps in order: write, review the first box, advance or return, then add new cards in small batches.
The routine runs in a fixed order so that nothing is skipped and the first box stays manageable. Each step has a clear pass condition and a known failure mode.
Start with writing: one fact per card, phrased so that you can answer it as right or wrong. Then review the first box daily, advance the cards you got right, return the cards you got wrong to the first box, and only then add new cards in small batches.
The main failure mode is overloading the first box: too many new cards at once makes the daily session unbounded and the routine collapses within a week.
The method runs from the 1880s to SM-18, built into SuperMemo 18 and 19.
Each card below is one step of the ordered daily procedure, with its failure mode.
Sources: the published milestones of spaced repetition from Ebbinghaus to SM-18 and the card-flow rules of the Leitner system.