Haven’t got Quartet, but I think the difference is likely to be in the themes covered. Tobira has a heavy focus on Japanese culture, tradition and significant historical events. It got a little overwhelming – and even boring – for me at the time because I wanted to know more about social customs and interactions in Japan, along with aspects of modern life (e.g. work culture, social issues, emerging trends). I ended up dropping Tobira around Chapter 13, and I’ve never gone back. However, to be fair, Tobira is from 2009, so some of the content is bound to be out of date. That isn’t really the authors’ fault. (Also, one caveat: I am a student who’s hoping to do a graduate degree in Japan soon, so perhaps that’s skewed my interests away from what Tobira covers.)
If Quartet is about working on all four language skills, then I think it’s likely to cover topics that allow more interaction with other people, and less of pure fact…
OK, I felt like I ought to check, and so I did. Based on everything I found on the official ‘What is Quartet?’ page, Quartet’s topics are indeed far more general and cater to a broader audience that is not deeply fascinated with every single aspect of traditional Japanese culture. Quartet’s ‘grammar points’ are also explained in much greater detail – Tobira’s explanations consist of about 3 long-ish sentences in English per grammar point, along with around 5 example sentences. Anyone self-studying will just have to infer the point of each illustrative sentence intuitively.
Oh, by the way, I think the font size in Quartet is significantly larger, and there’s much more space between lines. That should make it much less of a pain to read.
In terms of JLPT level, both claim to bring students to a similar level: Tobira was designed for JLPT Level 2, which was the 2nd highest level in the four-level system of the old JLPT; Quartet says N3 for Vol 1, and N2 for Vol 2, and the organisation behind the JLPT claims the N2 and the old Level 2 are about the same. I don’t know which to ‘believe’ – Quartet seems more recent and relevant, but Tobira’s texts were pretty challenging too. I will say that I was consistently unimpressed by Tobira’s grammar points though: never mind the lack of explanation, I had seen and learnt practically everything thanks to anime by the time I read each chapter.
In conclusion, here’s my opinion: take whichever of the books you fancy. What’s most important is that you feel fairly motivated and engaged by the content you’re studying. Still, given my experience with Tobira, and what I’ve seen of Quartet, I think Quartet is significantly better, and I would use it if I returned to the intermediate level today – the explanations are better, the structure is clearer, and it’s more aesthetically pleasing. Additionally, I think the vocabulary you’ll acquire with Quartet is way more useable in everyday life than what you see in Tobira, and more likely to appear on the JLPT (if that’s what you’re interested in). Quartet 2 also takes a decent shot at preparing students for independent study at the advanced level, with a clear, separate section on advanced content; Tobira doesn’t have that. It doesn’t really matter if Tobira actually (somehow) covers more grammar points if you’re not going to understand them well and remember them (especially if you’re not very experienced/comfortable with self-study). Besides, once you’re around the N3-N2 level, you should probably start working on native content more, which makes textbooks less important, in my opinion.
Once you’re done with intermediate textbooks, you essentially only have two options:
- Study one of the rare advanced high N2-N1 textbooks (I only know of two, and they’re both from the University of Tokyo)
- Work on your own
I own one of the textbooks for #1, but so far, I’ve mainly done #2, particularly with anime. It’s just so much more fun. Probably not the best way to acquire technical vocabulary though, so some diversification is necessary. (To paraphrase Apple though, ‘there’s an anime for that’ – Cells at Work, anybody?)
Anyhow, at the end of the day, I think it’ll always boil down to this: how do you think you can learn? Pick something that works for you. It doesn’t matter what reputation the other options have since no one’s going to judge you based on what intermediate textbook you used. At the very worst, you’ll learn the Tobira-only or Quartet-only knowledge somewhere else later on.