Once upon a time, I used to write Japanese lessons here on duolingo. Now, with the beta course finally being released for iOS, I realize that the lessons may not be needed any longer. However, since someone might not understand a certain grammar rule, or want to learn some new words that weren't taught in the course, here is a link to all of the lessons once again.
Making the lessons was helpful to me because explaining words and grammatical structures in depth really helped me with my own Japanese studies, and I can just hope that people find them useful for themselves. I just want to help this language spread out to more people who are commited and interested in learning.