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Spaced Repetition

Osmosis uses the Free Spaced Repetition Scheduler (FSRS) for all card scheduling. FSRS is the modern successor to the SM-2 algorithm and produces more accurate scheduling intervals based on memory research.

Ratings

After revealing a card's answer, rate your recall:

Rating Key Meaning Effect
Again 1 Forgot or wrong Card re-enters learning; interval resets
Hard 2 Recalled with difficulty Shorter next interval
Good 3 Recalled correctly Standard next interval
Easy 4 Instant, effortless recall Longer next interval

Card States

State Description
New Never studied — shown as "new" count in Dashboard
Learning Recently introduced, reviewed at short intervals
Review In long-term rotation, intervals growing
Relearning Previously known but forgotten, back to short intervals

Learning Steps

New and lapsed cards don't leave the session after one look. A card rated Again, or one still working through its learning steps, comes back within the same study session after a short delay.

Configure the delays in Settings > Osmosis:

Setting Default Applies to
Learning steps 1m, 10m New cards working toward their first real interval
Relearning steps 10m Review cards you rated Again

Enter a comma-separated list of intervals (m for minutes, h for hours). A card advances one step each time you rate it Good or better, and graduates to a normal FSRS interval after the last step. Rating Again sends it back to the first step.

If every remaining card is waiting on a timer, the study modal shows a "Waiting for next card" countdown rather than ending the session. A card's position in the steps is saved with its schedule, so closing the modal mid-session doesn't lose progress.

Tip

Leave the steps short. They exist to give a card a second look while it's still fresh — long steps just stall the session behind a countdown.

Daily Limits

Configure in Settings > Osmosis:

Setting Default Description
Daily new card limit 20 Maximum new cards introduced per day (0 = unlimited)
Daily review card limit 200 Maximum reviews per day (0 = unlimited)

Tip

Start with the defaults. If you're adding many cards at once, consider lowering the new card limit to avoid overwhelming yourself. Review limits rarely need changing.

Fixing a Card's Schedule

FSRS handles scheduling on its own, but sometimes a card needs a hand. The card browser is where that happens:

Situation Do this
A card keeps failing and its schedule is nonsense Reset it — scheduling clears, review history is kept
A card isn't relevant right now Suspend it — the schedule is preserved for later
A card is wrong Fix the note; the card follows
A card shouldn't exist Delete it from the browser

Everything except deleting is reversible, and deleting is undoable within the session.

Data Storage

All scheduling data lives in your markdown files — no external database. Fence cards store it inside the fence; line cards store it in the note's frontmatter under osmosis-schedule.

A fence that produces several cards gives each one a nested block named for the card it belongs to — r: for a bidirectional reverse, c1:, c2: … for cloze deletions and occlusion groups — while the fence's own card stays at the top level.

Data Storage has the complete format, including the review log that records every answer you give and feeds the statistics dashboard.

Why This Matters

  • No external database — Everything lives in your markdown files
  • Sync just works — Obsidian Sync, iCloud, Dropbox, or any file sync service carries your scheduling data automatically
  • Portable — Your review history travels with your notes
  • Transparent — You can inspect (but generally shouldn't edit) scheduling data directly