Tae Kim's "Japanese Grammar Guide" is found here: https://guidetojapanese.org/learn/grammar . This is what I am looking at for the main gist of my present desire to help myself in refining my Japanese language skills. ... Is it a good resource? I don't care, it has what I want and so it is a good resource from my point of view regarding my goals and desires and what I believe that I need to be focusing on. So yes, it is a good resource. ... What makes people think it is a bad resource? They are lazy, want to have the Genki Textbook style of language learning, yet wish that the Genki Textbook had the precision that this resource has without taking five textbooks to cover what this resource has in one book. For Japanese learners, there's a million different textbooks. There's "Japanese From Zero" which I originally used. There's the Genki Textbooks that my college courses preferred. But I have always wanted to devote time to this one, particular, resource. I believe it is a foundational textbook that allows one to truly make exceptional use of the other textbooks which is why, without being about to devote time to this one resource, I refuse to even look at the other textbooks that I have while I am in Japan. Grammar is a very important part of language learning. Vocabulary is a part of grammar, yes, but then so are the very crafted expressions of Japanese which one can more readily point to as "grammar" than the "X is Y which makes Z" formulas that English can be patterned through as if a mathematical discourse. I mean, it may also be the case that mathematics has been heavily used in the contemporary era by English speakers which is why a lot of English is especially mathematically seeming in nature, these days. Grammar points help exponentially increase the ability of oneself to express themselves. Vocabulary still needs to have it's meaning learned, too, and it's very specific in what it is referring to whereas "grammar" is extremely general so as to allow for more subtle and nuanced ways of expressing oneself without the necessitating lecture that merely having basic grammar and lots of vocabulary would produce. I can speak quite a bit in Japanese, yes, but it is a lecture for me to express what you can express in a soundbite or simple video. And that's just to be understood. Without the audience checks along the way, I wouldn't ever be able to be understood. And even then, the audience responses are requiring immense analysis precisely because the audience is simply free to pay attention and other things are more important to them such that at any moment, that can cloud their thinking and completely lose the understanding they had about what I was expressing. And then, if that happens, I have to try and figure out how to bring it back yet, also, it was likely not that important to begin with and really was just me trying to say "I love the design of the display and wanted to let you know that it is exceptionally amazing to have discovered".