Image Occlusion Flashcards: How to Make Them Well

Image occlusion flashcards hide part of an image — a label on a diagram, a structure on a scan, a component in a schematic — and ask you to recall what's underneath before revealing it. They're the right format for material you need to recognize visually, which a text-only card tests poorly no matter how well it's written.

Short answer

• Use image occlusion for material you need to recognize on sight, not just name from memory.
• Hide one label per card whenever possible — the same minimum information principle that applies to text cards applies here.
• Choose images with enough surrounding context that the hidden part is unambiguous.
• Hiding too many labels on one card lets you pass by getting most of it right while genuinely not knowing one part.
• StudyDaily displays and reviews imported image occlusion cards correctly; it doesn't currently include an editor to create new ones.

What image occlusion tests that text cards can't

A text flashcard asking "What is the coronary sinus?" tests whether you can define a term. It doesn't test whether you can find the coronary sinus on an actual diagram, which is a different and often more important skill for anatomy, geography, circuit design, or any field where you ultimately need to recognize a structure on sight rather than recite its name in isolation.

Image occlusion closes that gap by testing the visual recognition directly: you see the real image, one part hidden, and you have to produce what belongs there before checking. It's the same active-recall mechanism as a text card — see active recall vs. re-reading — applied to material where the image itself is the thing you need to know, not just a label describing it.

Applying the one-fact-per-card rule to images

The same principle that governs good text flashcards applies here: test one thing at a time. For an image, that means hiding one label per card whenever the material allows it, rather than blanking out an entire diagram's worth of labels and hoping you can name all of them in one pass.

See [[guide:write-better-cards-pillar|how to write flashcards you can actually remember]] for the full reasoning behind the minimum information principle. It applies just as directly to a hidden anatomical structure as it does to a hidden word in a sentence — a card that tests five things at once gives you an average grade for five different pieces of knowledge, which teaches the scheduler almost nothing precise about what you actually know.

How occlusion cards are typically created

Most people build image occlusion cards starting from a clear source image — a textbook diagram, a labeled scan, a schematic — then draw boxes over the specific elements they want to test, generating one card per hidden box or per group of related boxes.

Anki's ecosystem has long included dedicated image occlusion tooling, first through community add-ons and later as a built-in note type, and it remains one of the more common starting points for building this kind of deck. The official Anki manual documents the current occlusion feature if you're building cards in that environment. Whatever tool you use to create the cards, the underlying discipline is the same: pick a good source image, hide deliberately, and test one structure at a time.

Common occlusion mistakes

• Hiding too many labels on one card. The same overload problem as a crowded text card: you can pass by getting most of the hidden labels right while genuinely not knowing one, and the schedule never learns which specific piece is weak.
• Choosing an image with insufficient context. A hidden structure needs enough of the surrounding image visible to be identifiable — occlude too aggressively and the card becomes a guessing exercise rather than a real test of recognition.
• Using a low-quality or overly busy source image. A diagram that's hard to read even without anything hidden makes for a hard-to-review card regardless of how well the occlusion itself is designed.
• Occluding decorative or irrelevant parts of an image. Hide what you actually need to recall, not everything the image happens to contain — an occlusion deck built by hiding every visible label, whether or not it matters, produces a lot of low-value cards.
• Forgetting to vary which part is hidden across related cards. If you always hide the same corner of a recurring diagram type, you can start recognizing the pattern of what's hidden rather than the content itself.

Reviewing occlusion cards well

Apply the same honesty standard you'd use for any flashcard: try to identify the hidden structure before revealing it, rather than glancing at the general shape of the image and guessing from context. A hidden box surrounded by familiar landmarks can tempt you into pattern-matching your way to a correct answer without actually recalling the specific structure — that's the visual equivalent of a text card that leaks its answer through phrasing.

Grade based on whether you genuinely identified the hidden part, not on whether your final answer happened to be right. A lucky guess that gets marked "Good" schedules the same as real recall, which quietly weakens the review signal your scheduler is working from.

How StudyDaily handles imported image occlusion

StudyDaily displays and reviews imported image occlusion cards correctly, including the reveal mechanic and per-card scheduling under FSRS-6. It does not currently include an editor for building new occlusion cards from scratch — say that once and plan accordingly: build your occlusion deck in a tool that supports creation, then import the finished cards to study and schedule them here.

Once imported, occlusion cards behave like any other card type in StudyDaily: reviews run offline, on the device, with no account required to study. Open StudyDaily in your browser to test how an imported occlusion deck reviews before committing your full collection to it.

What should you do next?

Pick one diagram you actually need to know cold, build occlusion cards that each hide one label, and review them with the same honest grading you'd use for a text card.

• Choose source images with enough context that a hidden part is identifiable, not ambiguous.
• Hide one label per card whenever the material allows it.
• Vary which part is hidden across similar diagrams so you're not just pattern-matching the layout.
• Grade based on genuine recall of the hidden structure, not a lucky guess.

Questions people ask

What is image occlusion in flashcards?

It's a flashcard format that hides part of an image — a label, a structure, a component — and asks you to recall what's hidden before revealing it. It's built for material you need to recognize visually, like anatomy diagrams or schematics, rather than just define in words.

How many labels should I hide on one image occlusion card?

One whenever the material allows it. Hiding several labels at once lets you pass the card by getting most of them right while genuinely not knowing one, which produces a less accurate review signal than testing each structure separately.

Can I create image occlusion cards in StudyDaily?

Not currently — StudyDaily displays and reviews imported image occlusion cards correctly, including scheduling them with FSRS-6, but doesn't include an editor for building new ones. Create them in a tool that supports that workflow, then import the finished deck.

What makes a good source image for occlusion cards?

An image with enough surrounding context that the hidden part is identifiable without being obvious, and clear enough to read even before anything is hidden. A busy or low-quality diagram makes for a hard-to-review card regardless of how the occlusion itself is designed.

Sources used for this guide

The general image occlusion workflow described here reflects the official Anki editing manual, which documents the built-in occlusion feature in that application. StudyDaily's display, review, and import claims come from the product feature registry, checked for this guide's 3 August 2026 publication date.

Anki is a registered trademark of its respective owner. StudyDaily is not affiliated with, endorsed by, or sponsored by Anki. The product name is used here only to describe compatibility and to compare features.