What is a flashcard, and why does something this simple work

The oldest and most familiar form of a flashcard is probably what's coming to mind right now: a small paper card with a foreign word on one side and its translation on the other. It's a tool almost everyone runs into at some point while learning a language. The idea is so simple that at first glance it doesn't even occur to you to ask why it works so well.

How is it different from a "note"?

A lecture note carries information: a definition, an explanation, an example, all sitting right there in front of you. A flashcard, on the other hand, doesn't carry information, it asks for it. One side of the card holds a question, and the answer stays hidden. Before you see the answer, you're forced to try to find it in your mind, to recall it.

That small difference changes everything. Reading a note is a passive act, your eyes just move across the lines. Looking at a flashcard, on the other hand, actively pushes you to ask "what was that again?" Even if you can't come up with the answer, the effort of searching for it leaves a trace in your mind on its own. We cover this idea (active recall) in more detail in The Science.

From paper to digital: the real difference is timing

A box of paper flashcards doesn't tell you anything. You're the one who decides which card to review and when, and as we saw on the previous page, getting that timing right by hand isn't realistic.

This is where a digital flashcard app really differs from paper: it tracks when you saw each card and how easily or how hard you recalled it, then calculates exactly when the next review should happen on your behalf. You just look at the cards and answer them, the app handles the timing.

What does Tsunagi do?

Everything we've covered so far has been general: forgetting, spaced repetition, flashcards. Next is a quick look at how these come together in Tsunagi.