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§6.3

Line Separators and Breaks

A printed rule across the page—<hr/> or a page break?

✅ NormativeSettled. The requirement holds as written.📄 Page ruleCan be applied from the page alone.Read §6.3 in the RFC ↗

The requirement

A printed section separator MUST be rendered as <hr/>, at its place in reading order. --- MUST NOT be used for it: --- is reserved for page boundaries. A rule MUST NOT be inserted where the page prints only whitespace.

When it applies

A horizontal rule or separator printed between sections of a page. It is printed content: it tells a reader that one block has ended and another begun, so it survives into the output.

Sketch of the printed page — layout, not output
… end of the first section.
────────────────────────────        ← printed rule between sections  →  <hr/>
Start of the next section …

Reading the examples. Each one pairs a source page with the output the rule expects. ✅ Sample: the rule applies. ❌ Counter-sample: it looks like it applies and does not, or a rendering got it wrong. A non-conforming output, in red, is shown only for contrast. … marks content left out of an excerpt.

The point, in a small example

The first sample has a divider on one page. The second has two source pages. They require different separators. These pages are made up to isolate the rule.

01

✅ SampleConstructedThe rule applies

A printed divider is not a page boundary

Both labels are on one page with a visible divider. Use <hr/>; reserve --- for a change of page.

Source page
Line Separators and Breaks — A printed divider is not a page boundary. Source page.
Non-conforming output

What the rule rules out.

Markdown
Morning session

---

Afternoon session
Expected output
Markdown
Morning session

<hr/>

Afternoon session
Line Separators and Breaks · Source page

A printed divider is not a page boundary

Line Separators and Breaks — A printed divider is not a page boundary. Source page.
02

✅ SampleConstructedThe rule applies

Document structure continues across pages

Two consecutive interior pages are shown in order. The document title is on an earlier cover; sections use level 2 and subsections level 3. The running header is plain text on both pages. The printed folios stay in their footer bands; they are not physical sheet indices.

Source page
Line Separators and Breaks — Document structure continues across pages, image 1. Source page.
Line Separators and Breaks — Document structure continues across pages, image 2. Source page.
Expected output
Markdown
FIELD GUIDE

## 2 Maintenance

### 2.1 Inspection

Inspect daily.

Revision A · Page 4

---

FIELD GUIDE

### 2.2 Cleaning

Clean weekly.

Revision A · Page 5
Line Separators and Breaks · Source page

Document structure continues across pages

Line Separators and Breaks — Document structure continues across pages, image 1. Source page.
Line Separators and Breaks — Document structure continues across pages, image 2. Source page.

Requirements

  • Each printed separator between sections MUST produce one <hr/> line, placed between the elements it separates in reading order.
  • The separator MUST NOT be written as ---, ***, ___ or any other Markdown thematic break.
  • Vertical whitespace between sections, with no printed line, MUST NOT produce <hr/>.

Why never ---

--- is already load-bearing twice. It is the page-break marker of Markdown Rendering (§3.2), and at the top of a file it opens frontmatter. A separator that renders identically to a page break makes page attribution ambiguous for anything splitting on it, and can silently truncate a document at the top of a file. <hr/> avoids both collisions and follows the general posture of falling back to HTML wherever a Markdown spelling is ambiguous — see Text Formatting Conventions (§7.1).

More

Rule id layout-line-separators-and-breaks · rule layout model-divergence