narou.rs Setup Guide — Details
This page is a companion to the narou.rs Setup Guide. You do not need it to follow the steps; read it when you want to know why a step is done a certain way, or what the alternatives are.
On this page
- Two editions — which engine is used, switching editions, licensing, output comparison, rendering comparison
- Why AozoraEpub3 gets its own folder
- narou.rs folder layout
- Initialization (init) in detail
- Web UI address (port number)
- Add narou.rs to PATH (optional)
⚠️ Notice
- This article is not an official narou.rs manual. For anything unclear, prefer the latest information in the narou.rs README and Issues.
- Tested environment: Windows 11 (Japanese), narou.rs v0.3.4 (steps and screenshots) / v0.4.4 (behavior of the two editions, output comparison), AozoraEpub3 v1.4.0-jdk21 (steps and screenshots) / v1.6.1-jdk21 (output comparison), Thorium Reader 3.5.1 (rendering comparison)
Two Editions (v0.4.0 and Later)
Starting with v0.4.0, each narou.rs version is distributed as two different zips.
| Standard edition | GPL edition | |
|---|---|---|
| Zip name (64-bit Windows) | narou_rs_win_x64.zip |
narou_rs_win_x64-GPL.zip |
| EPUB conversion engine | External AozoraEpub3 (such as AozoraEpub3-JDK21) | Built-in AozoraEpub3_Lite (a Rust port of AozoraEpub3) |
| Java | Required | Not required |
| Downloading AozoraEpub3 | Required | Not required |
| License | BSD-2-Clause | GPL-3.0 |
Which Engine Is Used
Even with the GPL edition, if AozoraEpub3 is registered (via init -p, or AozoraEpub3 is on your PATH, etc.), that AozoraEpub3 takes precedence. The built-in engine is used only when no AozoraEpub3 can be found. This also means that the GPL edition needs Java when AozoraEpub3 is registered.
Also, without a registered AozoraEpub3, the gaiji fonts placed in AozoraEpub3’s gaiji folder are not used.
Switching Editions Later
Stop the Web UI (Ctrl+C) first, then download and extract the other zip, then copy the contents of the narou folder inside it into C:\Tools\narou, overwriting the existing files (choose “Replace the files”).
The edition fetched by self-update can be chosen with self-update.variant in the Web UI settings (Global tab): gpl = GPL edition / standard = standard edition.
Why the Licenses Differ
AozoraEpub3 (the original by hmdev and its derivatives, such as “Kaizōban (Modified) AozoraEpub3” by kyukyunyorituryo and AozoraEpub3-JDK21) is released under the GPL-3.0. When you distribute software that incorporates GPL code, the distributed software as a whole must be released under the GPL (the GPL’s copyleft takes effect). AozoraEpub3_Lite is a port of AozoraEpub3, so it is GPL-3.0 too. A narou.rs build that embeds it therefore becomes GPL-3.0 as a whole, which is why it ships as a separate zip from the BSD-2-Clause standard edition. The standard edition only launches AozoraEpub3 as a separate program, so it stays BSD-2-Clause.
The license difference only matters if you modify or redistribute the program. If you just download and use it, either edition is fine.
Output Comparison (Measured on This Site)
We converted four novels from Syosetu (including one long series with 1,404 episodes; 1,678 body files in total) from the same text data with the GPL edition’s built-in engine and with AozoraEpub3-JDK21 v1.6.1, and compared the results (narou.rs v0.4.4).
| Item | Result |
|---|---|
| Conversion | Succeeded for all four novels with both engines |
| Body text | Identical in every file |
| Ruby (including readings) | Identical in all 15 occurrences |
| Illustrations | Not verified (none of the novels had illustrations) |
| epubcheck 5.2.0 | No errors or warnings for either |
| Internal EPUB structure | Different. The built-in engine uses the same item/ layout as Kaizōban (Modified) AozoraEpub3 by kyukyunyorituryo (a fork that follows the DPFJ EPUB 3 production guide); AozoraEpub3-JDK21 uses an OPS/ layout |
| Heading and section-title markup | Different. For example, episode headings are <h2> in the built-in engine and <div class="chap2"> in AozoraEpub3-JDK21 |
The readable content is the same, but because the markup and CSS differ, the appearance, such as heading sizes and the layout of section title pages, may differ.
Rendering Comparison (in Thorium Reader)
We converted the same text with both engines and displayed the same pages side by side in the same EPUB reader.
- Text: Osamu Dazai’s “Run, Melos!” (Hashire Merosu) from Aozora Bunko (public domain), arranged in the same shape as a Syosetu novel (2 chapters, 3 episodes) and run through narou.rs’s normal conversion path
- Conversion: narou.rs v0.4.4 GPL edition. Left: built-in engine; right: with AozoraEpub3-JDK21 v1.6.1 registered (both with narou.rs default settings)
- Display: Thorium Reader 3.5.1 (Windows 11), same window size (700×900), default display settings. The images are the page area cropped and scaled down to 480px wide. The blue arrows on the left and right are Thorium’s page-turn buttons
- How they were made: the procedure and scripts in tools/narou-rs-compare (in Japanese) reproduce them
Rendering depends on the EPUB reader, so your reader may display things differently.
| Page | Built-in engine (GPL edition) | AozoraEpub3-JDK21 |
|---|---|---|
| Title page Title and author |
 |
 |
| Table of contents |  |
 |
| Chapter title page |  |
 |
| Episode text Heading and ruby |
 |
 |
The differences seen in this setup:
| Page | Built-in engine | AozoraEpub3-JDK21 |
|---|---|---|
| Title page | Title in a serif (Mincho) font, left-aligned, author below a rule | Title and author in a sans-serif (Gothic) font, centered |
| Table of contents | Episodes indented under chapters | Chapters and episodes as one flat bulleted list |
| Chapter title page | Running head and chapter title near the top center of the page | Running head and chapter title at the top-right edge (chapter title about the same size). From v1.7.0, the running head (work title) is a small vertical line beside the chapter title, and the page is centered when the work title is short |
| Episode text | Bold heading | Regular-weight heading. Body typesetting and ruby are the same |
Why AozoraEpub3 Gets Its Own Folder for narou.rs
During initialization (init -p), narou.rs rewrites one of AozoraEpub3’s configuration files (chuki_tag.txt). If you register a copy of AozoraEpub3 that you also use for other purposes, its other conversions are affected as well. So use a separate copy of AozoraEpub3 extracted into its own folder just for narou.rs (narou.rs itself recommends this).
narou.rs Folder Layout
After extracting the zip, the folder looks like this (the same for both editions).
C:\Tools\narou\
narou_rs.exe
narou_rs_updater.exe.new
narou_rs_backup.exe
narou_rs_login.exe
webnovel\
preset\
commitversion
LICENSE / README.md / Third-Party-License.md
narou_rs.exe relies on webnovel\, preset\, and commitversion being in the same folder. Do not move them elsewhere or delete them.
If you get “VCRUNTIME140.dll was not found” at startup, install the official Microsoft Visual C++ Redistributable (usually the x64 version; the ARM64 version on ARM-based Windows).
Initialization (init) in Detail
Output (Standard Edition)
On success, init -p prints something like this (narou.rs prints its messages in Japanese):
.narou/ を作成しました
小説データ/ を作成しました
webnovel/ を作成しました (6 files)
AozoraEpub3の設定を行います
!!!WARNING!!!
AozoraEpub3の構成ファイルを書き換えます。narouコマンド用に別途新規インストールしておくことをオススメします
AozoraEpub3 の構成ファイルを書き換えました
グローバル設定を保存しました
初期化が完了しました！
The !!!WARNING!!! refers to the chuki_tag.txt rewrite described above.
Output (GPL Edition)
When you run init (without -p) and press Enter without typing anything at AozoraEpub3のあるフォルダを入力して下さい (“enter the folder containing AozoraEpub3”), it still prints !!!WARNING!!! AozoraEpub3の構成ファイルを書き換えます… (“AozoraEpub3’s configuration files will be rewritten”) along the way. Nothing is rewritten when you skip registration, so you can safely ignore it. It ends with AozoraEpub3 の設定をスキップしました (“AozoraEpub3 setup skipped”) and 初期化が完了しました！ (“initialization complete”).
Options and Retrying
-pmust point to the folder where you extracted AozoraEpub3 (the folder containingAozoraEpub3.jar).- The line height defaults to 1.8×. Only add
-l 2.0or similar if you want to change it. - If the registration fails, just run
init -p ...again in the same folder (it will say the folder is already initialized, but the AozoraEpub3 configuration is redone).
Where to Run the Commands
The setup guide runs both init and web from a window opened in the novel folder (C:\Tools\narou-novels). If you use a PowerShell window opened from the Start menu instead, first run cd C:\Tools\narou-novels to move there.
Do not create the novel folder inside the narou.rs folder (C:\Tools\narou). narou.rs is designed to keep its own folder and your novel folder separate (as instructed by the official README).
Web UI Address (Port Number)
The Web UI address has the form http://localhost:(port number)/. The port number is chosen automatically on the first launch and reused from then on. The Web UI only runs on your own PC (localhost) and is not exposed externally.
Add narou.rs to PATH (Optional)
This lets you type just narou_rs instead of the full C:\Tools\narou\narou_rs.exe every time. Everything in the setup guide works without it (the official narou.rs README assumes a PATH-based setup, but running by full path behaves the same).
Paste the following two lines as-is into PowerShell and press Enter (run it only once), then close PowerShell and open a new window.
$narouPath = "C:\Tools\narou"
[Environment]::SetEnvironmentVariable("Path", [Environment]::GetEnvironmentVariable("Path", "User") + ";" + $narouPath, "User")
From then on, a newly opened PowerShell accepts the short form, such as narou_rs web.
To undo it: press the Start button → type “environment variables” → open “Edit environment variables for your account” → select Path in the upper box and press “Edit…” → select the C:\Tools\narou line and press “Delete” → close with “OK”.
← Back to the narou.rs Setup Guide