Skip to content

Spaced Repetition Systems

FSRS (Free Spaced Repetition Scheduler)

Per-neuron spaced repetition (stability, difficulty, next review date). FSRS v6 is a neural-network-based scheduler that outperforms SM-2 (Anki's default) on recall prediction accuracy.

  • Propagation never touches FSRS state — only affects pressure
  • Each neuron maintains independent stability and difficulty parameters
  • Grade mapping: miss → Again, weak → Hard, fire → Good, strong → Easy

References

  • Ye, J. (2024). FSRS: A modern spaced repetition algorithm. github.com/open-spaced-repetition/fsrs4anki
  • Wozniak, P. A. & Gorzelanczyk, E. J. (1994). Optimization of repetition spacing in the practice of learning. Acta Neurobiologiae Experimentalis, 54, 59–62.
  • Leitner, S. (1972). So lernt man lernen. Herder.