JLPT prep book series from ASK Publishing, split by level and by skill: grammar, vocabulary, kanji, reading and listening. Each book is a week-by-week plan with one short lesson per day, with English, Chinese and Korean translations for self-study.
11 Shin Kanzen Master (新完全マスター) alternatives
Other grammar tools, in our recommended order. About Shin Kanzen Master (新完全マスター) →
YouTube channel with hundreds of free Japanese lessons, best known for a series that walks through every chapter of the Genki textbooks, explaining the grammar and building practice sentences. Relaxed and funny enough to listen to on the go. His website, tokiniandy.com, adds paid companion courses with exercises and tests for Genki and Quartet.
Grammar study tool that teaches points by JLPT level and reviews them with fill-in-the-blank sentences on a spaced repetition schedule.
Free and very detailed Japanese grammar reference, running from beginner topics to classical Japanese.
Tae Kim's Guide to Learning Japanese: a free grammar guide that explains Japanese on its own terms rather than through English grammar.
Long-running free blog of Japanese lessons on grammar points and casual expressions, with many example sentences.
Free JLPT N5 to N1 grammar lessons with audio examples, explanations for every practice answer, listening practice, mock tests and Anki decks. No sign-up needed.
Sakubi: a short, free guide to Japanese grammar designed to get you reading real Japanese quickly rather than covering everything in depth.
Visualizing Japanese Grammar: free video lessons that explain grammar points with animated diagrams.
JLPT grammar book series from ASK Publishing, one book per level, that teaches grammar through short conversations and example sentences, then practises it.
A Dictionary of Japanese Grammar (Basic / Intermediate / Advanced)
Three-volume grammar reference published by The Japan Times. Each entry explains one grammar point in depth, with many example sentences, notes on usage and related expressions.