[dcw303]

5 or 6 grammar points can go a long way? If it's that few then I guess they must be the formal forms. So you'll need at least another 5 or 6 to understand the casual forms that you would use with friends or when you're the sempai in the situation. Want to talk to kids or young adults? Better learn another 5 or 6 forms of manga styled grammar slang. And if you interact with sales clerks, listen to train announcements or want to hear other official announcements, they're going to speak keigo, so there's another "5 or 6" forms to learn.