A Guide to Customize Kobo for New Simplified Chinese Readers

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Introduction
Here is a summary of the tools that I have used to customize my Kobo for reading Simplified Chinese (SC). It may also apply to users who read any other languages not natively supported by Kobo Nickel. I am really grateful for all the tools and posts available online, and I hope this summary will help some new Kobo users.

Effort required levels:
1- Zero effort
2- Require using existing tools
3- Require basic coding

System
Nickel
Details: Stay in the Nickel system and set the system language to Traditional Chinese (TC).
Effort: 1
Advantage: Personally, I buy books from Kobo store and borrow books from Overdrive, so it makes sense to stay in the Nickel ecosystem most of the time.
Disadvantage: Some characters have the same encoding in TC and SC, but they are slightly different in appearance. Therefore, using the default font (AR UDJingxihei) to read SC is nonideal. Fortunately, it can be easily resolved with font renaming described in the Font Section.
Comment: If I remember correctly, Kobo improved its Chinese language (TC) support in the UI in the past year.

Kobopatch by geek1011
Link: https://www.mobileread.com/forums/sh...d.php?t=297338
Effort: 2
Comment: It supports various customizations of the Nickel system. For example, before I found the font renaming trick, I used kobopatch to change the display font for dictionaries.

Koreader (https://github.com/koreader/koreader)
Link: I recommend using the one-click install package provided by NiLuJe https://www.mobileread.com/forums/sh...d.php?t=314220
Effort: 2
Advantage: SC is natively supported. A lot of functionalities. PS: My favourite function is Style tweaks> Miscellaneous>In-page footnotes.
Comment: I timed the transition between Nickel and Koreader. From Nickel to Koreader, it takes only 6 seconds, but the transition from Koreader to Nickel takes 20 seconds.
Comparison to Nickel: The only inconvenience I have is that the browse by Calibre tag function is less accessible in koreader than in Nickel (Calibre tag can be directly mapped to Kobo collections as in https://wiki.mobileread.com/wiki/Kob...nd_Collections).

Font
How to: make Nickel’s default fonts display SC
Steps: I kept the English UI and I renamed a serif font with SC to be Georgia, and a sans font with SC to be Avenir Next (renamed using fontforge as discussed below).
Background: The English interface of Nickel defaults to search missing glyphs in the Japanese font only, so a lot of SC characters cannot be displayed. With the renaming method, all SC characters can be properly displayed, since Nickel searches Georgia and Avenir Next for glyphs first.
Disadvantage: After each reboot, one must open a book so that Nickel can reload all custom fonts.
Warning: I’m not sure why, but some font files irritate Kobo and cause it to reboot upon opening SC books. Therefore, when you create new customized fonts, load them one by one to single out font files that may cause issues.
Credit: I saw a post by jackie_w and traced it to nkluan in https://www.mobileread.com/forums/sh...d.php?t=323372.

How to: read a SC book with multiple fonts
Steps: (1) If the language of a book is set to Chinese, Nickel will ignore font settings in css and always use AR UDJingxihei to display the entire book. Therefore, the language of the book must be set to English in order to display multiple fonts. (2) Then, in the epub stylesheet, each font-family attribute must be modified to a valid font family on the device. For example, if the Kobo displays a CS font name as “my font”, then the css can refer to “my font”. PS. For how to edit the epub, please refer to the Book Section.

Source: Noto fonts
Link: https://www.google.com/get/noto/; https://github.com/adobe-fonts/source-han-sans; https://github.com/adobe-fonts/source-han-serif
Note: There are both sans and serif fonts available.
Warning: Some files seem to cause Kobo to crash. PS. For any crash, just delete the problematic font file from Kobo and everything should be fine.

Tool: FontForge (https://github.com/fontforge/fontforge)
Usage: (1) Rename fonts in Element>Font Info. (2) Merge fonts as in https://superuser.com/questions/4909...ging-two-fonts
Warning: There seems to be a bug with FontForge to open Noto fonts.

Dictionary
Comment: I was extremely glad that Kobo updated its English and other dictionaries in the past year. Unfortunately, there is no SC or TC dictionaries provided by Kobo yet, so custom dictionaries would be needed.

How to: add dictionaries to Kobo
Link: instructions provided by geek1011 at https://pgaskin.net/dictutil/dicthtml/install.html
Effort: 2
Source: existing dictionaries in Kobo format
Link: A list compiled by Alberto Pettarin can be found at https://www.mobileread.com/forums/sh...d.php?t=232883
Effort: 1

Tool: Converting/merging from other formats using Penelope by Alberto Pettarin
Link: https://github.com/pettarin/penelope
Effort: 2
Disadvantage: The project is discontinued.
Advantage: It still works very well.
Note: You might want to patch this issue in your local copy: https://github.com/pettarin/penelope/issues/20.

Tool: Converting from Kindle dictionaries and others using PocketBookDic by Markismus
Link: https://github.com/Markismus/PocketBookDic
Effort: 2.5 (even though there is no need to write any code, the setup does take more time than other tools)
Comment: Given the recent dictionary updates by Kobo, there probably is less need for the Kindle to Kobo dictionary conversion.

DIY: Creating your own dictionary from custom sources with the help of dictutil by geek1011
Steps: For a dictionary I had available in a custom format, I (1) used Python to convert it to the df format as defined in https://pgaskin.net/dictutil/dictgen/ and then (2) compiled it with dictgen.
Effort: 3
Suitable scenario: When the dictionary you are looking for is quite niche, this is the only way to go.
Sidenote: Instead of using the merge function in dictutil or other tools, I merged two Chinese dictionaries together (one has less characters than the other) by just dragging the files in File Explorer and merging the words file, since each character corresponds to a different html file (which means that this won’t work for English).

Book Editor
Calibre by Kovid Goyal
Link: https://calibre-ebook.com/download
Effort: 2
Usage: Well, I’m sure everyone knows but just to reiterate. (1) Edit metadata in Calibre, since it’s not possible to type in SC on Nickel. (2) Edit epub stylesheet so that they have the same font name as the ones loaded on Kobo.

Sigil
Link: https://github.com/Sigil-Ebook/Sigil
Effort: 2
Comment: The Calibre ebook editor will likely suffice. This is another open-source tool that can be used to edit epub.

Python
Effort: 3
Comment: I suspect what I do in Python can be done in Calibre, but Python can serve as a last resort for customized editing.


I hope it helps! And what is your experience with SC or other languages not natively supported by Kobo?