December 21, 2021
Honestly, this is the only textbook I've ever enjoyed reading from start to finish. It doesn't get into advanced grammar, but it covers all the basics. I would estimate that it covers most if not all of N5/N4 and maybe into N3. It actually goes into more depth than most traditional textbooks since it uses native material. I think you will need additional textbooks/resources to really master Japanese grammar (for one thing, this doesn't have exercises), but I highly recommend this book to start.