What is the goal of your study? Do you want to be able to converse freely? Learn a few words? Get some appreciation of the culture? Translate documents for a living? I think the options will vary greatly depending on your answer to this...
I understand. I would like to be able to understand, at a deeper level, the words of O- Sensei and several other Japanese spiritual masters ( e.g. Dogen). Converse freely? Not sure, I would like to,but I will settle at passable conversatipn and being able to at least passably read a book or a newspaper.
All the best