We have an interesting discussion going on at a forum at LingQ on whether we need to learn grammar rules or patterns. Here is my latest comment on this subject, but there is quite a variety of views there.I agree that correct usage is all about mastering patterns that are generally accepted in the language as spoken by the natives. Of course the patterns may vary according to which tribe of natives we want to emulate, but language mastery is still about patterns. I believe that massive input, with a little help, whether from teachers, the odd correction, grammar books, self-help tools like LingQ or Anki, is the shortest path to the mastery of these patterns. I find the explanations of the patterns using a lot of grammatical jargon hard to follow. I prefer, “in Japanese they say things this way and it more or less means this”. Then I watch for the pattern and gradually get a clearer and clearer sense of what it really means, the more I come across it in my reading and listening.