Plangothic: a Source Han Sans extension covering CJK Unified Ideographs Extension B to J

A supplement to Source Han Sans rather than a typeface of its own

The Plangothic project is not trying to be a font family. The project documentation describes it as based on Source Han Sans that supplements the CJK Unified Ideographs extension area with glyphs drawn to the mainland China standard, and it calls itself one sub-project of a wider family of work that started around June 2020.

That framing explains the whole shape of the project. Source Han Sans already covers the ideographs a reader meets in ordinary Chinese text, so what is missing is the long tail of rarer characters, the ones that show up in names, place names, classical texts and archival texts. The scope section states that the font mainly supports all the Han characters from Extension B through Extension J, with only scattered characters from other blocks.

The audience is therefore narrow and real: a publisher typesetting a Chinese book that contains rare names, a localisation team facing a character their base font lacks, an archival project rendering historical text. The tool that serves them is a font, and the decision to evaluate is mostly a decision about coverage, licence and platform behaviour rather than about design.

The repository layout is consistent with a production pipeline. There is a sources directory, a tools directory, a registry directory, and a documentation directory holding sample images, and the repository links to a CI workflow named deploy-build-fonts, so the fonts are built automatically rather than assembled by hand.

Two font files because a single font caps out at 65535 glyphs

The first entry in the frequently asked questions explains why the project ships two font files rather than one. A font can hold a limited number of glyphs, 65535, and the total number of ideographic characters is far greater than that value. Splitting the coverage across two files is how the project gets past the ceiling.

The FAQ also explains why the collection includes a small number of characters from the Basic block and Extension A. The project exists to supplement Source Han Sans, so anyone who needs ordinary characters should use Source Han Sans directly. The scattered Basic and Extension A characters included here are the ones that either have a changed glyph in Unicode or do not match the purpose of the project, and the project states that each of those was compared against other mainstream fonts and the Unicode chart before being added.

That last detail is the part worth reading twice. A supplement that silently disagreed with its base font on a common character would be worse than useless, so the comparison step is what makes the small overlap safe. It also means the two fonts are not simply two halves of one set, and a user has to install both to see everything the project intends to cover.

A display font with no complex script layout and no variant selectors

The fourth FAQ entry states the sharpest boundary of the project. There is no complex text layout support and no ideographic variation selectors, and the reason given is that the font is intended as a tool font, meaning it is responsible for display and not for typesetting, in the way Unifont is. Rendering Arabic or Indic text accurately, or switching between regional glyph forms, is explicitly outside what the project covers.

For a Chinese reader of simplified text that is usually harmless. For a document that mixes scripts, or that needs the traditional Chinese or Japanese forms of a shared ideograph, the missing pieces matter. The FAQ closes by telling readers who need this to make their own derived font for their own requirements.

The third FAQ entry draws a similar line in a different direction. There will not be versions with other weights or other regional glyph forms, because the engineering effort would be too large, and the suggestion to anyone who wants that is the same: build a derivative for the need. So the project is deliberately a fixed point rather than a family, and anyone planning around it should plan around one weight and one regional standard.

TTC on desktop, partial rendering on phones

The fifth FAQ entry deals with the practical deployment question. The TTC file, which merges several TrueType fonts into one collection, works on Windows and can be used normally there. On a phone, installing the TTC file directly shows only one of the glyph sets, usually the first, and cannot show all of them at once. Using the collection inside an application may require extra settings to render everything, and the project notes that platform compatibility with TTC varies.

That is a real deployment constraint and it is not specific to this project. A TTC collection is a packaging format, and operating systems differ in how much of it they expose to the font manager. What the project adds is a statement that the project ships a TTC, and the consequence that a single install on a mobile device gives a fraction of the coverage.

The alternative packaging question is not answered by the project. There is no mention of a separate file per collection, of a web font build, of subsetting, or of a variable font. The releases are the source of the font files, and the badges link to the releases page for downloads. So an adopter who needs the full character set on a phone has to find out for themselves how the collection is distributed.

Two licences, one for the fonts and one for the tooling

The licensing is split, and the split is the right way round for this kind of project. The font files themselves are released under the SIL Open Font License 1.1, and the source code, scripts and configuration files in the repository are under the MIT License, which permits free use, modification and distribution including commercial use. The repository holds LICENSE-OFL.txt and LICENSE-MIT.txt separately, and the OFL badge links to the former.

The OFL permissions listed are generous. Any individual, group, organisation or enterprise can use the font for commercial and non-commercial purposes without paying, without notifying the author in advance, and without claiming credit or asking permission. The font can be redistributed, installed, or embedded into software or devices that are themselves distributed or sold. Modification, extension and format conversion are allowed, with two conditions: a modified work may not use the reserved names Plangothic or 遍黑, and a modified version must be published under the SIL Open Font License, unless the change is a pure format conversion.

The prohibitions are specific. The font file itself may not be sold on its own, although it can be bundled into software or hardware that is sold, and no part of it may be published under a different licence. A disclaimer follows, separate from the licence terms, in which the author states that users may use the font freely subject to local law and that the author accepts no liability for system damage or legal disputes.

The project also warns that the author has never authorised anyone to sell the font files individually, that paying for a font file from a third party may be misleading or fraudulent, and that the OFL permits bundling the font as part of other paid software or hardware.

The caution notice, and the AI question it raises

The documentation opens with a caution block that is unusual for a font project, and it is worth reading in full because it describes risks to the user rather than to the author.

The first item reports that this font and many other open source fonts have been resold by unscrupulous merchants on platforms such as Taobao and Xiaohongshu, in violation of the clause in SIL OFL 1.1 that forbids selling the font file on its own, and asks buyers not to purchase from such shops, since the money would not reach the author and the buyer would get no updates and no support. The second item addresses organisations whose legal departments do not accept the effect of the OFL and require a traditional authorisation certificate, and recommends giving up on the font in that case and using a free commercial font that can issue one or buying a commercial licence. The third warns against AI generated fonts trained on this font or its upstream, because the training data is unknown and the result carries legal risk, and states that the project was developed without any AI technology.

Those three items map onto the real decisions a procurement or legal reviewer has to make, and the second one in particular is the reason to read the licence rather than assume it. A font that is free for commercial use is not automatically usable inside a large organisation that documents every dependency.

Version numbering that tracks Unicode, and a release in mid 2026

The release tags are unusual and informative. The most recent is V2.9.5795, labelled as the 20260705 update and published on 2026-07-05. Before it came V2.9.5792, labelled the 20260101 update and published on 2026-01-01, and before that V2.9.5787, labelled the 20250911 update from 2025-09-11.

The numbers read as a build identifier rather than a semantic version. The minor component moves across the whole year, and the build component increments as new characters are added, so each release corresponds to a snapshot of the Unicode coverage at that date. A team that pins a version is pinning a set of characters, and the tag itself tells you when that set was assembled. This is more informative than a plain patch number, and it also means the release list is effectively a changelog of coverage growth.

The last push was on 2026-09-26, which is after the July release, so work on the main branch is not reflected in the newest tag. The project ships its documentation in four languages, with README.md, README.en.md, README.ja.md and README.zh.hant.md at the top level, and the badges link to a QQ group number for discussion. A contributor list is given, with four names credited as the main producers and a further set credited with technical assistance.

Editorial conclusion

Plangothic is a reasonable choice for a Chinese publishing, localisation or archival project that needs the Extension B to J ideographs in a black sans design and can accept a display only font with no complex script layout and no regional variant forms, and it is the wrong choice for a team that needs vertical text shaping, Arabic or Indic support, or a second weight built the same way. Before adopting it, install the TTC on the target platform and confirm the glyphs you need actually render, because the project states that mobile devices installing a TTC show only one face of the collection, and read LICENSE-OFL.txt for the reserved name rule, since a modified version may not be called Plangothic or 遍黑.

Frequently asked questions

Official sources

1. Fitzgerald-Porthmouth-Koenigsegg/Plangothic_Project on GitHub
2. Issues
3. License: MIT
4. README
5. Releases