The Feynman Technique and the Leitner System
Josh Sanders (compiling Feynman and Leitner) · 2026
"Genuine understanding is tested by whether you can explain a concept simply enough for a child, and genuine retention is engineered by spacing review intervals according to how well you already know the material — two separate mechanisms that most study habits conflate into one vague 'studying' activity."
If you can't explain it simply, you don't understand it yet. That's the entire Feynman Technique in one sentence.
The Feynman Technique has four steps: select a topic and study it, explain it in plain language as if teaching a child, identify the specific gaps where your explanation breaks down or gets vague, then return to the source material to fill exactly those gaps. The Leitner System handles the separate problem of retention over time: flashcards move between boxes reviewed at different frequencies (3x/week, 2x/week, 1x/week) based on how reliably you're recalling them, so your limited review time concentrates on what you're actually failing rather than re-reviewing what you already know cold.
What distinct problem does the Leitner System solve, separate from the Feynman Technique?
Read more about the topic
The explanation above is written with AI assistance. These are the originals — go to them to check it.
- Master the Art of Learning — How to Remember and Retain KnowledgeX (Twitter) infographic
The Feynman Technique: The Ultimate Guide to Learning Anything Faster
"You don't actually understand something until you can explain it in plain language a 12-year-old could follow — complexity and jargon are usually masking a gap in your own understanding, not evidence of sophistication."