Evidence-based answer · Last updated · How it’s made
The sources don't name specific advanced-grammar textbooks or apps, but they do point to what actually helps at advanced levels: reading lots of real Japanese material (extensive/pleasure reading), studying example sentences rather than just rule explanations, and getting explicit grammar explanations paired with practice and feedback rather than mechanical drills alone. In short, "resources" matter less than how you use them — combine a source of clear explanations with heavy exposure to real sentences and some form of feedback.
Asked as someone learning Japanese. Findings drawn from Japanese-specific research are framed for Japanese learners and may not hold for other languages; where the evidence is general second-language research, the report says so.
In a survey of Japanese-as-a-foreign-language learners in the UK, the highest-rated way of learning new grammar was reading example sentences and working them out themselves, rated higher than any other exercise type, including mechanical drills, which got the lowest rating.1
Most JFL learners preferred a teacher to first explain a new grammar point, but then wanted to examine examples themselves rather than have everything spelled out; very few wanted to skip grammar explanation entirely or figure the rule out fully on their own before instruction.1
The same survey found learners rated grammar knowledge as more useful for reading and writing than for listening or speaking, and a quarter of respondents felt grammar got in the way when trying to speak in real time.1
A study of Japanese learners found that reading extensively for enjoyment (rather than translating texts word-by-word) was rated as more encouraging and motivating, and is linked in the broader reading research to picking up vocabulary and grammar patterns naturally, plus faster reading.3
In plain terms
Example
Learners who had been trained mainly through grammar-translation methods showed a strong 'accuracy-first' mindset that made them uncomfortable with speed reading (reading fast without stopping to fully parse every grammatical structure), even though the study argues this kind of practice helps build reading fluency.3
A study of Japanese EFL learners found that writing something yourself, then comparing it to a native-like model text, and having a teacher add explicit grammar explanation afterward, produced better learning of a target grammar structure than writing practice alone.2
In plain terms
Example
General second-language research finds that explicit grammar instruction (direct explanation of rules) speeds up learning and can raise final proficiency, especially when combined with lots of exposure and communicative practice — it doesn't replace immersion, but it isn't useless either.5,7
In plain terms
Research comparing different styles of correcting learners' grammar mistakes (some subtle, some very direct) found that both styles can help learning, though studies disagree on which works better in which situation.4
One study of teacher trainees found that even though many favored more natural, meaning-focused grammar teaching in general, they still leaned toward traditional, explicit, rule-first teaching specifically for higher-level learners.6
Since none of the sources name specific advanced Japanese grammar books or apps, base your resource choices on what the research shows actually helps: 1) Pick materials that give clear rule explanations plus lots of real example sentences to study on your own — the Japanese-learner survey found this combination was rated far more useful than mechanical fill-in-the-blank drills. 2) Read extensively in Japanese at a level you mostly understand — novels, graded readers, articles — rather than relying only on textbook grammar exercises or translating line by line; this builds a feel for advanced grammar patterns in context and was linked to more motivation and fluency. 3) When you have a grammar point you're targeting, try writing something yourself, comparing it to a native-written version, and getting explicit correction on the mismatches — this "notice the gap" approach outperformed writing practice alone in the studies reviewed. 4) Don't discard explicit grammar explanation just because you're advanced — the broader SLA research suggests direct rule instruction still has value at higher levels when paired with real practice and feedback, so a resource that only offers immersion with zero explanation, or only offers isolated rule drills with no real input, is likely to leave a gap.
Now pick something to do it with
Each of these opens an overview of the apps, courses and immersion material worth a look for that — filtered to exactly what the advice above points you at:
Or see the full resource list