Books for Learning Japanese: What Each Kind Is Actually For
The short answer
Buy a textbook for sequencing, a grammar reference for looking things up, and a graded reader for practice — and understand that these are three different purchases, not three versions of the same one. The commonest mistake is buying a reference and expecting it to teach, or buying a textbook and expecting it to answer questions.
This note describes the categories rather than ranking specific titles, because the right book depends on which of the six stages of the self-study route through Japanese you are stuck on, and because a book nobody has used cannot honestly be rated.
Why a book at all, when apps exist
Because grammar is a reasoning job and apps are a memory tool. A multiple-choice exercise can be passed by recognising the shape of the right answer without ever forming the rule, which is why so many app-only learners can complete hundreds of lessons and still not know why one particle was correct.
Prose fixes that. A paragraph can say "this marks the topic, that marks the subject, here is the difference and here is where it matters" — a sentence-matching exercise cannot, and is not trying to.
The second reason is offline depth. A reference book gives you somewhere to look things up that is organised by concept rather than by search term, which matters when you do not yet know the name of what is confusing you.
The four categories, and what each one is for
The textbook: sequencing
A textbook's real product is order. It decides what you meet in which week, keeps vocabulary within what has been introduced, and gives you exercises that test the thing just taught. That is genuinely valuable and it is the one job apps also do well, so buy a textbook when you want a spine for the first year rather than because a book is inherently better.
Signs you bought the right one: the dialogues are in kana and kanji rather than romanised; there is an audio component; and it expects you to write. Signs you bought the wrong one: it is organised by topic ("at the restaurant", "at the post office") rather than by grammar, which makes it a phrasebook with homework.
The grammar reference: answering questions
A reference is not read front to back; it is consulted. Its value is in being organised by the thing you are confused about, with enough examples to see the pattern, and it becomes useful at roughly the point a textbook starts feeling thin — usually somewhere in the second half of a first year.
The free options here are strong. Several comprehensive Japanese grammar guides are published free online by their authors, and for a self-studier's first year they answer most of what comes up. Buy a printed reference when you find yourself looking the same thing up repeatedly and wanting it on a desk rather than in a browser.
The kanji book: order and mnemonics
A kanji book sells you a sequence and a memory system, and whether you need one depends entirely on whether you are able to build your own. If your spaced-repetition deck is working and characters are arriving from your reading, you do not need a book; if you keep abandoning decks, buying somebody's order is worth the money.
The alternative is a curated online course, which does the same job with the reviews built in. WaniKani, from Tofugu, is the best-known; its own front page advertises "2,000 kanji. 6,000 vocabulary words. In just over a year", and it does not print its subscription price in its page source, so no figure for it appears here. That headline is a claim about the course and assumes daily reviews without gaps.
The graded reader: mileage
Graded readers are books written with controlled vocabulary and grammar so that you can read at speed instead of decoding. They are the least glamorous purchase on this page and the one that most reliably moves reading forward, for the reason set out in how to learn to read Japanese: volume of text read is what turns recognition into comprehension.
Free graded material exists too. NHK WORLD-JAPAN publishes free Japanese learning material, and its own framing of the three-script problem is as clear as anything in print: "Hiragana and Katakana are phonetic symbols, each representing one syllable while Kanji is ideogram, each stand for certain meaning."
What about a dictionary
A paper dictionary is a hobby, not a tool. Electronic lookup that lets you search by drawing a character, by radical or by pasting text is strictly better for a learner, because the bottleneck is identifying an unfamiliar character rather than alphabetising.
Where a printed dictionary still earns its place is for usage: books that explain the difference between near-synonyms, or that catalogue particles and set phrases with examples, do something a lookup tool does not.
How to tell a book will go unread
Three warning signs, learned expensively.
It is enormous. A 600-page reference bought in month two is a monument, not a study aid; the book that gets used is the one whose next section is fifteen minutes away.
It has no audio. Japanese rhythm and vowel length are not recoverable from the page, and a beginner reading silently builds a pronunciation that will need unlearning.
It is romanised past the first chapter. That is a marketing decision aimed at people who have not learned kana, and it makes the book useless the moment you have — which, per which Japanese alphabet to learn first, should be a fortnight in.
What a book cannot do
No book supplies correction or speaking practice, and both of those are the stages where self-study actually stalls. A book will not tell you that the sentence you produced was grammatically correct and socially wrong, which in Japanese is a whole category of error — register is encoded in the grammar, so a learner can be both right and rude.
That is what an hour with a teacher is for, and it is why the honest reading list for a self-studier is short: one textbook, one reference, one reader, and the rest of the budget spent on somebody who answers back.
A minimal shelf
If you want the whole answer in four lines: a textbook with audio for the first year; a free online grammar guide bookmarked; a graded reader you actually finish; and a spaced-repetition habit, which costs nothing because Anki's desktop software is free and open source and AnkiDroid for Android is free too.
Add a kanji book only if your own deck keeps collapsing. Add a printed reference only when you notice you are looking the same thing up for the fifth time. Everything beyond that is shopping, which is one of the more enjoyable ways to avoid studying.