I think renshuu is a very good option to practice your grammar. The explanations are also good but in my opinion they are not enough to fully understand the grammar point. Additionaly to practicing grammar with renshuu, I'd recommend you to also watch grammar videos on YouTube because they ore often very in-depth. The best one's I know are Japanese ammo with Misa (Her videos are very long but also really helpful), Miku real Japanese and Kaname Naito. There are also a lot of websites that help with grammar. For grammar I also use Bunpro sometimes. There, you also have good explanations and you can practice there.
Renshuu does help with grammar, but other apps like duolingo, while it does help with some words, it doesn't even help you get halfway to complete fluency. Renshuu helps you get much closer to fluency, but still might not completely help you become fluent.
You can find Renshuu's grammar lessons in the menu under "Japanese Lessons". Check them out and see if the format is helpful to you, and if you want to test yourself on them, you can click "Manage your schedules" on the dashboard and add the "Japanese Basics" set of schedules.
The core of Renshuu, the SRS quizzes, is built around supporting any materials you choose to learn with. If you prefer not to use Renshuu's grammar lessons, you can use any textbook or audio lesson or Youtube channel or whatever works for you, and still use Renshuu's schedules and grammar library to reenforce what you're learning.
if you find that the lessons themselves dont explain the grammar well enough, i found that it was helpful to watch the videos they’re in resources under japanese lessons. then you click the little video icon next to the grammar piont that you want to watch. unfortunately not all of the lessons have videos but the ones that do are explained more thoroughly in the video than in the actual lesson
In addition to the Japanese Basics Lessons on Renshuu (which cover JLPTN5 to JLPTN4) , there are grammar pages covering 900+ grammar points all the way from from JLPT N5 to JLPTN1.
Each grammar page has:
-description
-outline of the construction
-example sentences
-user notes
-a discussion thread for the grammar point
Renshuu has community lists of the grammar points organized by textbook, JLPT level, etc. for convenient addition to a grammar schedule, where you can test your skills using real sentences.
Additionally, when looking at sentences, if you hover your mouse over the words it will show you the grammar point that is likely being used.
I studied N5+N4 with Bunpro, TaeKim and Cure Dolly (youtube), but for me the explanations on Renshuu were superhelpfull. Many points clicked much more. But in general I think it's a good idea to check out multiple resources for the points you're struggling with.
I found Tae Kim often a bit too brief. Cure Dolly.. she explains fantastic but her voice makes it a bit hard to listen to. Bunpro.. its really great to practice grammar with but the explanations are a bit problematic.
Especially for grammar that uses multiple words with a subtile difference (like all the 'looks like, seems like variations) Bunpro doesn't explain those differences really well, or even not at all.
Fingers crossed the N4 lessons will be completed soon on renshuu. It was a bit confusing that the N4 schedule doesn't include the vocab and explanations as the N5 schedule did, and that I had to find the N4 lessons in a completely different section in the app :)
they’re in resources under japanese lessons. then you click the little video icon next to the grammar piont that you want to watch. unfortunately not all of the lessons have videos
but the ones that do are explained more thoroughly in the video than in the actual lesson
