Kunten / kaeriten (訓点・返り点)

Kunten are the marginal annotations Japanese readers add to classical Chinese (漢文) source so that it can be read in Japanese word order. The two categories aozora handles:

1. Kaeriten (返り点) — reading-order marks inserted between characters: レ, 一, 二, 三, 上, 中, 下, 甲, 乙, 天, 地, 人.
2. Saidoku-moji (再読文字) — characters that are read twice with different glosses (e.g. 未, 将, 当).

A handful of late-Edo / Meiji Aozora Bunko works carry these. The notation:

有﹅レ朋﹅自﹅遠﹅方﹅来

…where ﹅ stands in for the actual kaeriten character. In real source the marks are interleaved between characters using either the direct character or a ［＃…］ annotation:

有［＃二］朋自遠方来［＃一］

Notation forms

Inline (preferred in modern works)

The kaeriten character is inserted directly between the source characters:

有レ朋自遠方来

Renders as:

有<span class="aozora-kaeriten" data-aozora-kaeriten="レ">レ</span>朋自遠方来

Bracketed (older works)

有［＃二］朋自遠方来［＃一］

Renders as:

有<span class="aozora-kaeriten" data-aozora-kaeriten="二">二</span>朋自遠方来<span class="aozora-kaeriten" data-aozora-kaeriten="一">一</span>

The bracketed form is useful when the kaeriten character would otherwise be ambiguous with the surrounding text (e.g. a real 一 that is not a reading mark).

Saidoku-moji

未［＃「未」に二の字点］

The 二の字点 / 一二点 prefix tells the renderer that the preceding character is read twice. aozora emits a data-aozora-saidoku data attribute on the wrapper.

AST shape

pub struct Kaeriten<'src> {
    pub mark: KaeritenKind,    // Re | Ichi | Ni | San | Jou | Chuu | Ge | Kou | Otsu | Ten | Chi | Jin
    pub form: KaeritenForm,    // Inline | Bracketed
    pub span: Span,
}

pub struct Saidoku<'src> {
    pub target: &'src str,     // the character being re-read
    pub gloss:  &'src str,     // the second reading
    pub span:   Span,
}

Why a flat enum, not just &str?

The 13 kaeriten kinds form a closed set fixed by the spec — there will never be a 14th. A KaeritenKind enum lets the renderer match exhaustively (the compiler catches unhandled variants), and pins the data-aozora-kaeriten attribute value to a stable slug rather than the literal source character. That matters because the inline form uses the actual 一 / 二 / 上 / … glyphs, which are also valid plain text — the enum lets the AST distinguish “a 一 that’s a kaeriten” from “the digit one in the running text”.

Diagnostics

See also

• Notation overview — the orientation map for all the inline annotations.