Metadata

Metadata is a set of information associated with a work, such as its title, author, publisher, among others. Different formats have different ways of storing and representing metadata. Bunko Shelf will try to extract as much metadata as possible from a manga or book, but it will not always be possible. For example, PDF files usually lack good metadata support, and manga archive files (CBZ/CBR) often have malformed or missing metadata.

Manga, Comics, and Others (CBZ/CBR)

Metadata is extracted from the ComicInfo.xml file found inside CBZ and CBR archives when present. Currently Bunko Shelf is based on the 2.0 standard schema from The Anansi Project and can detect and extract metadata from the following XML template (which you can use to add and/or adapt your mangas' metadata).

<?xml version="1.0" encoding="utf-8"?>
<ComicInfo>
    <Title></Title>
    <Series></Series>
    <Number></Number>
    <Count></Count>

    <Summary></Summary>

    <Year></Year>
    <Month></Month>
    <Day></Day>

    <Writer></Writer>
    <Penciller></Penciller>
    <Inker></Inker>
    <Colorist></Colorist>
    <Letterer></Letterer>
    <CoverArtist></CoverArtist>
    <Editor></Editor>

    <Publisher></Publisher>
    <Imprint></Imprint>
    <Genre></Genre>
    <Tags></Tags>
    <Web></Web>
    <PageCount></PageCount>
    <LanguageISO></LanguageISO>
    <Format></Format>
    <Manga></Manga>

    <AgeRating></AgeRating>
    <CommunityRating></CommunityRating>
    <GTIN></GTIN>
</ComicInfo>

Genre and Tags

The fields for genre <Genre> and tags <Tags> must be filled in lowercase, without spaces between them, and separated by commas: school,slice of life,shonen,yuri. Spaces are allowed if they are part of the genre or tag.

Reading Orientation

While mangas are often read right-to-left, Bunko Shelf allows specifying the reading direction using the <Manga> tag. According to the standard, Bunko Shelf supports these four values:

Unknown: Not specified (default is assumed right to left).
No: Not a manga and is read left to right.
Yes: Is a manga and is read right to left.
YesAndRightToLeft: Is a manga and is read right to left.

Manga with Western Orientation

For mangas that are read from left to right, we have added an additional non-standard value YesLTR for the <Manga> tag. This value indicates that the manga is of Japanese style but is read from left to right.

Books (EPUB)

Metadata is extracted from the .opf file found inside EPUB files. Currently, Bunko Shelf is based on the OPF 2.0.1 (EPUB 2) standard from IDPF and the Package Document (EPUB 3.3) standard from W3C, and can detect and extract metadata from the following templates (which you can use to add and/or adapt your books' metadata with applications such as Sigil or, alternatively, Calibre).

OPF 3 (EPUB 3)

<?xml version="1.0" encoding="UTF-8"?>
<package>
  <metadata>
    <dc:identifier>MOBI-ASIN:0000000000</dc:identifier>
    <dc:identifier id="uuid_id" opf:scheme="UUID">urn:uuid:00000000-0000-0000-0000-000000000000</dc:identifier>
    <dc:identifier id="isbn" opf:scheme="ISBN">9780000000000</dc:identifier>
    
    <dc:title>Main title</dc:title>
    <dc:title>Optional subtitle</dc:title>

    <meta property="belongs-to-collection" id="series-name">Series name</meta>
    <meta refines="#series-name" property="collection-type">series</meta>
    <meta refines="#series-name" property="group-position">1</meta>
    
    <dc:creator opf:role="aut" opf:file-as="Last name, First name">First name Last name</dc:creator>
    <dc:contributor opf:role="trl" opf:file-as="Last name, First name">Translator's name</dc:contributor>
    
    <dc:publisher>Publisher</dc:publisher>
    <dc:date>2026-09-12</dc:date>
    <dc:language>en</dc:language>
    
    <dc:description><![CDATA[
      <p>Book synopsis.</p>
    ]]></dc:description>
    
    <dc:subject>Genre or tag</dc:subject>
    
    <dc:rights>© 2026 Rights holder's name</dc:rights>
    <dc:source>Original source or edition identifier</dc:source>
    <dc:type>Text</dc:type>

    <meta name="rating" content="16+"/>
    <meta name="cover" content="cover"/>
    <meta name="primary-writing-mode" content="horizontal-lr"/>
  </metadata>
</package>

OPF 2 (EPUB 2)

<?xml version="1.0" encoding="UTF-8"?>
<package>
  <metadata>
    <dc:identifier>MOBI-ASIN:0000000000</dc:identifier>
    <dc:identifier id="uuid_id">urn:uuid:00000000-0000-0000-0000-000000000000</dc:identifier>
    <dc:identifier id="isbn">urn:isbn:9780000000000</dc:identifier>
    <meta refines="#isbn" property="identifier-type" scheme="onix:codelist5">15</meta>

    <dc:title id="title-main">Main title</dc:title>
    <meta refines="#title-main" property="title-type">main</meta>
    <dc:title id="title-subtitle">Optional subtitle</dc:title>
    <meta refines="#title-subtitle" property="title-type">subtitle</meta>
    
    <meta name="bunko:series" content="Series name"/>
    <meta name="bunko:series-type" content="series"/>
    <meta name="bunko:series-position" content="1"/>
    
    <dc:creator id="author-01">First name Last name</dc:creator>
    <meta refines="#author-01" property="role" scheme="marc:relators">aut</meta>
    <dc:contributor id="translator-01">Translator's name</dc:contributor>
    <meta refines="#translator-01" property="role" scheme="marc:relators">trl</meta>
    
    <dc:publisher>Publisher</dc:publisher>
    <dc:date>2026-09-12</dc:date>
    <dc:language>en</dc:language>
    
    <dc:description><![CDATA[
      <p>Brief book synopsis.</p>
    ]]></dc:description>
    
    <dc:subject>Genre or tag</dc:subject>
    
    <dc:rights>© 2026 Rights holder's name</dc:rights>
    <dc:source>Original source or edition identifier</dc:source>
    <dc:type>Text</dc:type>
    <meta property="schema:typicalAgeRange">16+</meta>
    
    <meta property="rendition:layout">reflowable</meta>
    <meta property="rendition:flow">paginated</meta>
    <meta property="rendition:orientation">auto</meta>
    <meta property="rendition:spread">auto</meta>
    <meta name="cover" content="cover"/>
  </metadata>
</package>

Contributors

Bunko Shelf preserves any contribution role in OPF 2 and OPF 3. The roles that currently have their own label in the UI are:

Code	Displayed as
`aut`	Author
`bkp`	Digital production
`bjd`	Design
`bkd`	Design
`cmp`	Composition
`cov`	Design
`dsr`	Design
`edt`	Editing
`ill`	Illustration
`nrt`	Narration
`pht`	Photography
`tyd`	Design
`trl`	Translation

Age Rating

Bunko Shelf interprets the <AgeRating> tag in the ComicInfo.xml file as a recommended minimum age for reading. It does not accept direct numeric or arbitrary values. In contrast, the OPF 2 and OPF 3 files for books support only the numeric values in the following table:

Age (reflected in Bunko Shelf)	Valid value in <AgeRating>
0+	`G` `Early Childhood` `Everyone`
6+	`Kids to Adults`
10+	`Everyone 10+` `PG`
13+	`Teen`
15+	`MA15+`
16+	`M`
17+	`Mature 17+`
18+	`Adults Only 18+` `R18+` `X18+`
No age (null)	`Unknown` `Rating Pending`

Age Rating Tags

For Bunko Shelf to correctly recognize the age rating, it is important to use exactly the tags mentioned in the table above within the <AgeRating> field of the ComicInfo.xml file. Only one age rating value can be added in the <AgeRating> tag. If multiple values or an unrecognized value are provided, Bunko Shelf will not apply any age rating to the manga.