What is the sentence mining method?

The sentence mining method is building your flashcards from whole sentences you meet in real material, instead of memorising words off a list, so each card teaches a word with its grammar and the situation it belongs to. You find a sentence you almost understand, turn it into a card with the meaning and native audio, and review it with spaced repetition so it comes back just before you'd forget it.

The name comes from digging useful sentences out of real input (a book, a show, a sign, a voice note) and keeping the ones that teach you something. The sentence you can nearly read is what you mine; the one new word or piece of grammar inside it is what you keep. A line with five unknowns is too hard to be a good card. One gap is the sweet spot.

It caught on in the Japanese-learning community in the late 2000s, and it rests on a plain idea from Stephen Krashen: you learn most from input one step past your level, his i+1. A whole sentence you almost understand is i+1 you can hold in your hand. If you want the practical version, here is how you actually do sentence mining.