The Aozora Bunko Notation Specification

Status: Draft v0.1.0 · Date: 2026 · License: Apache-2.0 OR MIT

This document specifies 青空文庫記法 (Aozora Bunko notation): the inline and block annotation language used to mark up plain-text works in the Aozora Bunko digital library — ruby, emphasis dots and side lines, gaiji (out-of-repertoire glyph) references, kunten / return marks, layout containers, page and section breaks, and editor annotations.

It is written to be implementable from the text alone: it uses RFC 2119 keywords, an ABNF grammar, an explicit processing model, a diagnostics catalogue, and a machine-readable conformance suite.

This specification is an independent formalisation. It is not affiliated with or endorsed by Aozora Bunko. The authoritative human-facing source is the official 注記一覧 (https://www.aozora.gr.jp/annotation/); where that source is silent or ambiguous, this document makes an explicit normative decision and records the rationale.

See §1 Introduction to begin.