Lemma

A modern, FSRS-powered spaced repetition plugin that lives inside your notes.
No separate app. No manual data export. Write, tag, and study directly where your knowledge lives.

     

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Preview

Desktop and mobile · LaTeX math support · Learning analytics · Custom study sessions

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Why Lemma?

Most spaced repetition tools require leaving your knowledge base, exporting notes, and managing a secondary database. Lemma embeds spaced repetition directly in Markdown.

Notes are decks. Add #flashcards to any note, write cards in plain Markdown, and let FSRS handle scheduling.

Feature	Lemma	Anki	Standard SR Plugins
Native Markdown workflow	Yes	No	Yes
FSRS scheduling	Yes	Yes (addon)	Partial
Mobile support	Yes	Yes	Varies
LaTeX / rich Markdown	Yes	Yes	Varies
Cross-device sync (CouchDB)	Yes	Yes	No
Custom study sessions	Yes	Yes	No
Zero file clutter	Yes	N/A	Varies
Open source	Yes	Yes	Yes

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Features

FSRS Scheduling

Lemma uses FSRS (Free Spaced Repetition Scheduler), a modern scheduling algorithm developed from cognitive science research. It models memory stability and retrievability based on your individual recall patterns.

Cards Live in Notes

Write flashcards directly in any Markdown note without imports or app switching.

---card--- ^fsrs-abc123
What is the powerhouse of the cell?
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**Mitochondria** — produces ATP through cellular respiration.

Cloze Deletions

The ==c1::mitochondria== is the powerhouse of the ==c2::cell==.

Each cloze deletion is scheduled independently.

Dashboard View

View all decks in a single overview with due counts, new cards, and total reviewed.

Custom Study Sessions

Filter review queues by tag, card state (new, learning, due), or configure a card limit for targeted study and exam preparation.

Review Statistics

Analyze learning progress with retention curves, card maturity distribution, interval histograms, 30-day activity, and 7-day forecast charts.

Mobile Support

Responsive review interface designed for desktop and mobile, with safe-area insets and touch-optimized navigation.

In-Place Image Occlusion

Review anatomy and technical diagrams in place without vertical shifting. Diagram cards automatically detect image pairs, swapping masks in the exact same viewport position with tap/peek toggling.

Type-In Active Recall

Type answers directly into the review card with instant character and keyword difference highlighting before revealing FSRS rating buttons.

Guided Card & Deck Creation

Interactive creation modals with dropdown format selection, live syntax previews, and automated deck tagging so you never have to memorize card syntax.

Optional CouchDB Sync

Connect to self-hosted CouchDB or Cloudant instances to sync review history seamlessly across devices.

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Quick Start

1. Install from Community Plugins: search for Lemma.
2. Add #flashcards to any note's frontmatter or inline:

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tags: [flashcards]
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3. Write a card:

---card--- ^my-first-card
What is spaced repetition?
---
A learning technique that schedules reviews at increasing intervals to maximize long-term retention.

4. Open the Lemma dashboard from the status bar or Command Palette (Open dashboard).

Full syntax documentation: FLASHCARD_GUIDE.md

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Card Formats

Lemma supports seven card and study formats:

1. Basic Multi-Line Cards

Multi-line format with full Markdown, LaTeX math blocks, and code formatting.

---card--- ^basic-001
What is the function of the ribosome?
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Protein synthesis via translation of mRNA.

2. Single-Line Cards

Fast atomic flashcards on a single line.

What is the capital of Japan?::Tokyo ^single-001

3. Bidirectional (Reversed) Cards

Generates a two-way recall card where the prompt and answer are tested in reverse.

Mitochondria:::Powerhouse of the cell ^rev-001

4. Cloze Deletion Cards

Hide one or more concepts in context. Multiple cloze IDs (c1, c2) schedule independent review items.

The ==c1::Ebbinghaus== forgetting curve shows memory decays without ==c2::spaced repetition==. ^cloze-001

5. In-Place Image Occlusion Cards

Swaps occluded diagrams with revealed answers in-place without vertical displacement. Tap the image or press Space / P to peek back and forth between masks before rating.

![[anatomy-masked.png]]::![[anatomy-revealed.png]] ^occlusion-001

6. Type-In Active Recall Cards

Prompts you to type your answer and provides instant character and keyword comparison before revealing ratings.

?type What is the SI unit of electric current?::Ampere ^typein-001

Or in block format:

---card--- ?type ^typein-002
What is the powerhouse of the cell?
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Mitochondria

7. Whole-Note Review

Apply FSRS spaced repetition to entire notes by adding #review to the frontmatter or body.

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tags: [review]
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# Quantum Mechanics Overview

Tip

Add a ^block-id to cards so review history persists across content edits.

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Keyboard Shortcuts & Gestures

Shortcut / Gesture	Action
Space / Enter	Reveal answer
Space / P / F	Toggle peek between question and answer masks (image cards)
1	Again (reset learning steps)
2	Hard
3	Good
4	Easy
Esc	Exit session
Swipe left	Rate Again
Swipe down	Rate Hard
Swipe right	Rate Good
Swipe up	Rate Easy

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Commands

Command	Description
Create card (guided modal)	Open guided creator modal with type selector and live preview
Create new deck	Create a new note pre-tagged with the deck tag
Tag current note as flashcard deck	Add the deck tag to the active note
Add a new flashcard	Insert a card template with a pre-generated block ID
Add a single-line card	Insert a single-line card template
Add a reversed card	Insert a bidirectional card template
Add a cloze card	Insert a cloze deletion template
Create cloze from selection	Wrap selected text in cloze syntax
Add a type-in card	Insert a type-in card template
Add a type-in single-line card	Insert a single-line type-in template
Open dashboard	Open the Lemma deck overview
Sync now	Trigger a manual CouchDB sync
Check sync status	View sync connection status
Review due notes	Start whole-note review session
Reset all card progress	Reset all scheduling data

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Settings

Setting	Description
Deck tag	Tag identifying deck files (default: flashcards)
Max new cards/day	Daily limit on new card introductions
Max reviews/day	Daily limit on review cards
Review font size	Font size in the review modal
FSRS parameters	Algorithm weights and retention target configuration
PouchDB storage	IndexedDB storage engine for collections
Sync	CouchDB connection and credential settings

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Installation

Community Plugin Directory

1. Open Settings → Community plugins
2. Click Browse and search for Lemma
3. Select Install, then Enable

Manual Installation

1. Download main.js, manifest.json, and styles.css from the latest release
2. Copy the files into:

   <vault>/.obsidian/plugins/lemma-flashcards/
   

3. Reload Obsidian and enable the plugin under Settings → Community plugins

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Support

If you find Lemma helpful for your studies and daily knowledge retention, you can support development:

• Buy Me a Momo
• Star the repository on GitHub

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Contributing

Contributions, bug reports, and feature requests are welcome.

• Issue tracker: GitHub issues
• Pull requests: Open a pull request against main

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License

ISC License — see LICENSE for details.