The Tadoku Graded Readers: NPO 多言語多読's Free and Print Series Explained

Tadoku graded readers are the flagship 多読 (extensive-reading, or reading a lot at an easy level) book line from NPO 多言語多読, available as both a free web library and paid Ask and Taishukan print sets spanning Levels 0 to 5.¹ They are the oldest and largest graded-reader line for Japanese, and the only major one with a no-account free on-ramp.¹²

Overview

This article focuses on the series itself: what is free versus paid, what the free web library contains, how the Level 0 to 5 system maps to the JLPT, and how to open the library and start your first book. For the broader background on what a graded reader is, what 多読 means, and the four reading rules, see the hub article on Japanese graded readers and how to start reading at your level rather than the explanation below.

What the Tadoku series is

The word "Tadoku" attaches to a whole family of books supervised by one non-profit, rather than to a single product. Knowing the organization behind the line is the fastest way to tell the free, legitimate releases apart from the unauthorized scans that circulate under the same name.

NPO 多言語多読, the organization behind it

The series is supervised and promoted by NPO 多言語多読 (English: NPO Tadoku Supporters), a Japanese non-profit. Its stated mission is to spread tadoku among people learning or teaching Japanese by presenting books that are fun and easy to read. The goal is for readers to want to read more and more, resulting in tadoku, or "quantity reading."³

The activity began in 2002, when a Japanese-language teacher founded a volunteer study group (日本語多読研究会) that produced handmade graded readers by trial and error.⁴ The group was incorporated as an NPO on 22 August 2006.⁴ In 2012 it merged with the English extensive-reading activity led by 酒井邦秀 (Sakai Kunihide) and took its present name, NPO 多言語多読 TADOKU Supporters.⁴

The NPO does not publish every book itself. It supervises five separate series from five publishers, only one of which, the free Web Tadoku Books, costs nothing.¹

The 多読 movement, its four rules, and the comprehensible-input rationale are covered in the hub article, so this deep dive links to them rather than re-teaching them. One rule is worth quoting here because it governs how you pick a Tadoku level later: "Don't use your dictionary."⁵

Why this is the series to know first

The Tadoku line is the oldest Japanese graded-reader series, tracing to the 2002 handmade readers and the 2006 published line.¹⁴ It is also the largest by title count: the Ask series alone holds the greatest number of books, in excess of 120.¹

It is the only major Japanese graded-reader line with a free, no-account web library as its on-ramp.¹² It also carries an explicit, publisher-authored JLPT correspondence chart, which makes it especially easy to map for learners orienting themselves by JLPT level.⁶

What's free and what's paid

Five publishers sit under the NPO umbrella. For learners, the most useful split is free versus paid: one free digital library, plus paid print and app lines that share the same editorial standards.

The free NPO web library (tadoku.org)

The Web Tadoku Books (labelled "Free Tadoku Books") are the NPO's own free digital readers, created by NPO members and marked "＊FREE" on the series list.¹ Each free title can be read in the browser ("読む," read), downloaded as a PDF and printed into a booklet, and, for many titles, watched as a video version on YouTube.²

Many titles carry 朗読音源付き (narration audio) and ふりがな付き (furigana throughout), and a subset of the easiest are ひらがなのみ (hiragana only, no kanji), which suits a reader who has just finished the kana.²

The free books are released under a Creative Commons BY-NC-ND 4.0 license: attribution to "NPO多言語多読" is required, use must be non-commercial, and no derivatives are allowed.⁷ Reading, printing, classroom use, and personal study are permitted. Altering the text or illustrations, adding your own translations, explanations, or tests, producing and publishing your own audio, reposting to YouTube, Instagram, or other social media, and commercial resale are all prohibited.⁷

The free library is the NPO's own release, not a piracy mirror

These PDFs are published directly by NPO 多言語多読 under CC BY-NC-ND 4.0, so reading, printing, and using them in class with attribution is fully legitimate.⁷ That is distinct from the Internet Archive scans of the paid Ask print sets, which are not authorized.⁷

The Ask Publishing print series (にほんごたどく / Tadoku Library)

The Japanese Graded Readers, published by Ask Publishing (アスク出版) under the Japanese title にほんご よむよむ文庫, were first published in 2006.¹⁴ The title can be read as "Japanese reading-reading library." This is the largest catalogue: more than 120 books over the series' history. The current line is described as 86 books organized in 16 packs, covering Levels 0 to 4.¹

The format is physical books with accompanying audio on CD or mp3 download.¹ The paid packs are sold as boxed sets.

Taishukan にほんご多読ブックス

The Taishukan Japanese Readers, published by Taishukan (大修館書店), launched in 2016.¹ The line spans Levels 0 to 5 across 55 books in 10 packs. It is the source of Level 5 books that are not available from other publishers, making it the only print line that reaches the top tier.¹ The content is fairy tales, novels, and cultural material with illustrations, and the packs are paid.¹

Two more NPO-published lines round out the choices at the lower levels. The Nihongo Tadoku Books print imprint is a fixed set of 9 books at Levels 0 to 3 (Aesop's tales and fairy tales), sold individually for roughly a few hundred yen each.¹ White Rabbit Press publishes the same 9 titles as paid apps for PCs, tablets, and smartphones.¹

Don't confuse the 9-book paid set with the free web library

The NPO's purchasable Nihongo Tadoku Books is a fixed 9-title Level 0 to 3 set, sold per book.¹ The free Web Tadoku Books is a separate, larger, and growing collection.¹² The similar names trip up searchers who assume "the NPO's books" means one thing.

Free vs. paid at a glance

Series	Publisher	Format	Cost band	Audio	Levels	Best for
Web Tadoku Books	NPO 多言語多読	Browser / PDF / YouTube	Free (CC BY-NC-ND)7	Many titles 朗読音源付き2	0–4 (heavy at 0–1)2	No-cost entry; trying tadoku before buying
Japanese Graded Readers (にほんご よむよむ文庫)	Ask Publishing	Print + CD/mp3	Paid (boxed packs)	CD / mp31	0–41	Largest curated print catalogue
Taishukan Japanese Readers (にほんご多読ブックス)	Taishukan	Print	Paid (boxed packs)	Illustrated; print1	0–51	The only print Level 5 titles1
Nihongo Tadoku Books	NPO 多言語多読	Print	Paid (per book, low)	n/a	0–31	Individual cheap titles1
Nihongo Tadoku Books app	White Rabbit Press	App	Paid (per book, low)	App1	0–31	Phone/tablet reading1

The free library: what is actually in it

The free library is the natural starting point, but its contents are uneven, and knowing the shape in advance prevents the "raw archive dump" frustration that hits learners who expect a complete course.

How the free titles spread across levels

The free web library is heavily concentrated at the bottom and thins sharply toward the top. This is the opposite of where many learners assume the value sits.² The visible distribution is thick at the Start, Level 0, and Level 1 tiers. It drops to a handful of titles at Level 2, a few at Level 3, roughly one at Level 4, and no free titles at Level 5.² The page lazy-loads, so treat these as a shape rather than a fixed catalogue count.

The practical takeaway is simple: the free library is an excellent free runway for absolute beginners through Level 1, but it is not a complete course.² A serious reader above Level 2 will exhaust the free titles quickly. After that, they will need the paid Ask or Taishukan packs, or native material such as children's books or simplified NHK news.²

Audio, furigana, and video versions

A title is audio-equipped when it shows 朗読音源付き (narration audio); the NPO recommends reading while listening.²⁷ Most free titles are ふりがな付き (furigana throughout). The very easiest are ひらがなのみ (hiragana only), with no kanji at all, which suits a reader fresh off the kana.² Many lower-level titles are also flagged YouTubeあり (YouTube available) and have a narrated video version on the NPO's channel.²

The Level 0–5 system and how it maps to JLPT

The Tadoku reader levels are the series' own grading scale, defined by the publisher rather than by the JLPT. The NPO publishes a mapping to JLPT bands, and it contains the single most error-prone fact in this topic.

How the levels are defined

The publisher (the NPO), not the JLPT, sets levels on three axes: a controlled vocabulary size, a target total words per book, and a grammar inventory that widens at each step.⁶ The table below uses the publisher's own figures.⁶

Tadoku reader level	Publisher descriptor	Vocab	Words per book	Grammar the reader meets
Level 0	Starter	350	200–400	です・ます, present/past, interrogatives, ～たい6
Level 1	Beginner	350	400–1,500	same grammar as Level 0, longer stories6
Level 2	Upper-Beginner	500	1,500–3,000	dictionary form, て-form, ない-form, ～と, ～から, ～なる, ～のだ6
Level 3	Lower-Intermediate	800	2,500–6,000	potential form, imperative, ～とき, ～たら/ば/なら, compound verbs6
Level 4	Intermediate	1,300	5,000–15,000	causative/passive, ～そう, ～らしい, ～はず, ～もの6
Level 5	Upper-Intermediate or Above	2,000	8,000–25,000	function words, idiom, honorific forms, abstract vocabulary6

Level 0 is built for starting beginners. It is printed left to right, uses a tightly controlled starter vocabulary, and includes hiragana-only titles.⁶

Level-to-JLPT map

The publisher attaches a rough JLPT band to each reader level. The mapping is below. The warning under it is the fact most worth slowing down for.

Tadoku reader level	Approx. JLPT band
Level 0	N5 (below–N5 entry)6
Level 1	N56
Level 2	N46
Level 3	N36
Level 4	N3–N26
Level 5	N2–N16

Two number scales that run in opposite directions

The JLPT is a five-band scale where N5 is the easiest and N1 is the hardest.⁸ The tadoku chart phrases each tier as "Level N of JLPT," counting the easy end as 5, so its "Level 5 of JLPT" means N5, the easiest band, not the hardest.⁶ That runs opposite to the Tadoku reader numbering, where Level 5 means the hardest books (N2–N1).⁶ Read "Tadoku reader level" and "JLPT band number" as two separate scales, and never read "Tadoku Level 5" as "JLPT N5."

Treat each band as guidance, not a guarantee. One Tofugu reviewer who had sat the N2 found the top tier easier than advertised. She pegs Level 5 as JLPT N2–N1 but, having taken the N2, found it "more in the N3 range," and suggests moving on to native content around Level 3 or 4.⁹

How to download and start

This section walks you from "open the site" to "reading my first book." It then covers how to pick a level and decide when a paid set is worth it.

Reading or downloading from the free library

The path from the free-books page to your first finished read is short.²⁷

Open the Free Tadoku Books page (tadoku.org, then Japanese, then Free Tadoku Books).² Click a title's free icon to read it in the browser ("読む," read), or download the PDF and print it into a booklet.² For a title flagged 朗読音源付き (narration audio), play the narration and read along, which the NPO recommends. For one flagged YouTubeあり (YouTube available), watch the narrated video version.²⁷

These files are the NPO's own CC BY-NC-ND 4.0 release: free to read, print, and use in class with attribution.⁷

Picking your starting level

Start at or below Level 0 / Level Start.⁶ Level 0 is built for starting beginners, with a tightly controlled starter vocabulary and hiragana-only titles. It is a safe floor even if you suspect you can read higher.⁶ Apply the page test from the four rules: if a page needs more than a couple of look-ups, drop a level. The method asks you not to reach for a dictionary and to put down anything that turns into work.⁵ For the why behind starting below your level, see the reading-strategy articles. This is just the rule of thumb.

Because the free library is thick at Levels 0 and 1 and thin above, a beginner can run an entire first phase on free material before spending anything.²

Log the free titles you finish in a spaced-repetition tool

A finished-book log can double as a vocabulary source. Drop the words you kept sight-reading at Level 0 into an SRS deck, where they are FSRS-scheduled and mapped to your level. That way, the runway through the free library also seeds your review queue. Keep it light; the point of tadoku is volume, not turning every page into flashcards.

Buying the print sets

Buy the paid Ask (にほんご よむよむ文庫) or Taishukan (にほんご多読ブックス) packs when you want physical books, curated level-by-level packs, and bundled CD or mp3 audio.¹ The other reason to buy is reach. Paid packs give you titles the free library lacks, especially Level 5, which only Taishukan publishes.¹

You are paying for format, packaging, audio, and the breadth of curated titles, not better writing.¹ The free and paid lines share the same NPO editorial principles.¹³

Good to know

"Tadoku" is a method, a movement, and a brand name at once

The single word "tadoku" can refer to three layers that searchers often conflate. 多読 (tadoku) is the extensive-reading practice, meaning the "read a lot" method.³ NPO 多言語多読 is the organization that propagates it.¹³ And にほんごたどく / にほんご よむよむ文庫 is a specific series brand.¹ A learner who searches for "tadoku" may land on the philosophy, the organization, or the product without noticing they are different things.³

Free and paid share the same editorial lineage

The free Web Tadoku Books and the paid Ask and Taishukan sets are all supervised by the same NPO and built on the same graded-reader principles.¹ The free books are created by NPO members, not a lesser tier.¹ Here, free does not mean lower quality. The difference is format and catalogue size.¹⁷

The JLPT mapping is a guide, not a guarantee

A learner reading the tadoku chart can mistake "Level 5 of JLPT" for "the hardest JLPT level." It means the opposite: "Level 5 of JLPT" is N5, the easiest band. The Tadoku reader Level 5 (N2–N1) is the hard one, so the two numbers point in opposite directions.⁶⁸ Beyond the direction trap, the publisher's tiers are not the JLPT itself. One N2-qualified reviewer found Tadoku Level 5 nearer N3 in practice, so treat each band as approximate.⁹

See also

• Japanese Graded Readers: What They Are and How to Start Reading at Your Level
• Satori Reader: Adaptive Graded Reading with Audio
• Crystal Hunters: The Manga Written for Beginner Japanese Learners
• NHK News Web Easy: A Daily Reading Routine for Simplified Japanese News
• Can You Learn Japanese From Children's Books? An Honest Guide to 絵本 (Ehon)
• The i+1 Principle for Reading Japanese

References

Footnotes

1. NPO 多言語多読 (NPO Tadoku Supporters). "Our Graded Readers." https://tadoku.org/japanese/en/graded-readers-en/ ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³ ↩¹⁴ ↩¹⁵ ↩¹⁶ ↩¹⁷ ↩¹⁸ ↩¹⁹ ↩²⁰ ↩²¹ ↩²² ↩²³ ↩²⁴ ↩²⁵ ↩²⁶ ↩²⁷ ↩²⁸ ↩²⁹ ↩³⁰ ↩³¹ ↩³² ↩³³ ↩³⁴ ↩³⁵ ↩³⁶

2. NPO 多言語多読 (NPO Tadoku Supporters). "Free Tadoku Books." https://tadoku.org/japanese/en/free-books-en/ ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³ ↩¹⁴ ↩¹⁵ ↩¹⁶ ↩¹⁷ ↩¹⁸ ↩¹⁹

3. NPO 多言語多読 (NPO Tadoku Supporters). "Our Vision." https://tadoku.org/en/vision-en ↩ ↩² ↩³ ↩⁴ ↩⁵

4. 内閣府 (Cabinet Office of Japan), NPO法人ポータルサイト. 「多言語多読」法人情報. https://www.npo-homepage.go.jp/npoportal/detail/013005859 ↩ ↩² ↩³ ↩⁴ ↩⁵

5. NPO 多言語多読 (NPO Tadoku Supporters). "How to do Tadoku." https://tadoku.org/en/l-method-en ↩ ↩²

6. NPO 多言語多読 (NPO Tadoku Supporters). "About levels." https://tadoku.org/japanese/en/levels-en/ ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³ ↩¹⁴ ↩¹⁵ ↩¹⁶ ↩¹⁷ ↩¹⁸ ↩¹⁹ ↩²⁰ ↩²¹

7. NPO 多言語多読 (NPO Tadoku Supporters). "Guide to Using Our Free Tadoku Books." https://tadoku.org/japanese/en/free-books-en/note-en/ ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰

8. The Japan Foundation / 国際交流基金, Japanese-Language Proficiency Test (JLPT) official site. "Linguistic Competence Required for Each Level." https://www.jlpt.jp/e/about/levelsummary.html ↩ ↩²

9. Suvannasankha, Emily / Tofugu. "Japanese Graded Readers: A Primer." Tofugu. https://www.tofugu.com/japanese/japanese-graded-readers/ ↩ ↩²