It's called "muscle" memory. This is no different than how pianists play piano from memory. They don't actually recall every individual keys but it's the connec

It's called "muscle" memory. This is no different than how pianists play piano from memory. They don't actually recall every individual keys but it's the connections between keys that matter. Ask people to write Chinese words or play pieces of music from arbitrary starting points and you will see their struggle. This is because you're breaking up the sequence into individual parts, which is not people learn things. To put it in an Anglo-Saxon perspective, when someone asks you whether the letter n is before r you may likely recite the alphabet from start to finish. So you know the answer but to get it you have to rely on some more"muscle" memory. I am also sure this happens when people try to spell certain words. They can't visualize exactly the word but once they start writing or typing it they get into the flow.