diff --git a/docs/vfm.md b/docs/vfm.md
index 2715ae1..14527aa 100644
--- a/docs/vfm.md
+++ b/docs/vfm.md
@@ -12,6 +12,7 @@ Vivliostyle Flavored Markdown (VFM), a Markdown syntax optimized for book author
 - [Image](#image)
   - [with caption and single line](#with-caption-and-single-line)
 - [Ruby](#ruby)
+  - [Escape pipe in ruby body](#escape-pipe-in-ruby-body)
 - [Sectionization](#sectionization)
   - [Plain section](#plain-section)
 - [Raw HTML](#raw-html)
@@ -169,8 +170,6 @@ figure figcaption {
 
 ## Ruby
 
-<Badge type="warning">PRE-RELEASE</Badge>
-
 **VFM**
 
 ```
@@ -192,6 +191,22 @@ ruby rt {
 }
 ```
 
+### Escape pipe in ruby body
+
+If want to escape the delimiter pipe `|`, add `\` immediately before it.
+
+**VFM**
+
+```
+{a\|b|c}
+```
+
+**HTML**
+
+```html
+<p><ruby>a|b<rt>c</rt></ruby></p>
+```
+
 ## Sectionization
 
 Make the heading a hierarchical section.
diff --git a/src/plugins/ruby.ts b/src/plugins/ruby.ts
index 2777c62..b5fb73c 100644
--- a/src/plugins/ruby.ts
+++ b/src/plugins/ruby.ts
@@ -10,7 +10,8 @@ function locateRuby(value: string, fromIndex: number) {
 
 const tokenizer: Tokenizer = function (eat, value, silent) {
   const now = eat.now();
-  const match = /^{(.+?)\|(.+?)}/.exec(value);
+  ///const match = /^{(.+?)\|(.+?)}/.exec(value);
+  const match = /^{(.+?)(?<=[^\\|])\|(.+?)}/.exec(value);
   if (!match) return;
 
   const [eaten, inlineContent, rubyText] = match;
diff --git a/tests/ruby.test.ts b/tests/ruby.test.ts
index 04c3019..7510fec 100644
--- a/tests/ruby.test.ts
+++ b/tests/ruby.test.ts
@@ -1,79 +1,36 @@
-import { stripIndent } from 'common-tags';
-import { buildProcessorTestingCode } from './utils';
+import { stringify } from '../src/index';
 
-it(
-  'simple ruby',
-  buildProcessorTestingCode(
-    `{a|b}`,
-    stripIndent`
-    root[1]
-    └─0 paragraph[1]
-        └─0 ruby[1]
-            │ data: {"hName":"ruby","rubyText":"b"}
-            └─0 text "a"
-    `,
-    `<p><ruby>a<rt>b</rt></ruby></p>`,
-  ),
-);
+const options = {
+  partial: true,
+  disableFormatHtml: true,
+};
 
-it(
-  'enables escape in ruby body',
-  buildProcessorTestingCode(
-    `{a\\|b|c}`,
-    stripIndent`
-    root[1]
-    └─0 paragraph[1]
-        └─0 ruby[1]
-            │ data: {"hName":"ruby","rubyText":"b|c"}
-            └─0 text "a\\\\"
-    `,
-    `<p><ruby>a\\<rt>b|c</rt></ruby></p>`,
-  ),
-);
+it('Simple ruby', () => {
+  const received = stringify(`{a|b}`, options);
+  const expected = `<p><ruby>a<rt>b</rt></ruby></p>`;
+  expect(received).toBe(expected);
+});
 
-it(
-  'disables any inline rule in <rt>',
-  buildProcessorTestingCode(
-    `{a|*b*}`,
-    stripIndent`
-    root[1]
-    └─0 paragraph[1]
-        └─0 ruby[1]
-            │ data: {"hName":"ruby","rubyText":"*b*"}
-            └─0 text "a"
-    `,
-    `<p><ruby>a<rt>*b*</rt></ruby></p>`,
-  ),
-);
+it('Enables escape in ruby body', () => {
+  const received = stringify(`{a\\|b|c}`, options);
+  const expected = `<p><ruby>a|b<rt>c</rt></ruby></p>`;
+  expect(received).toBe(expected);
+});
 
-it(
-  'nested ruby',
-  buildProcessorTestingCode(
-    `{{a|b}|c}`,
-    stripIndent`
-    root[1]
-    └─0 paragraph[2]
-        ├─0 ruby[1]
-        │   │ data: {"hName":"ruby","rubyText":"b"}
-        │   └─0 text "{a"
-        └─1 text "|c}"
-    `,
-    `<p><ruby>{a<rt>b</rt></ruby>|c}</p>`,
-  ),
-);
+it('Disables any inline rule in <rt>', () => {
+  const received = stringify(`{a|*b*}`, options);
+  const expected = `<p><ruby>a<rt>*b*</rt></ruby></p>`;
+  expect(received).toBe(expected);
+});
 
-it(
-  'ruby with newline',
-  buildProcessorTestingCode(
-    `{a\nb|c}`,
-    stripIndent`
-    root[1]
-    └─0 paragraph[3]
-        ├─0 text "{a"
-        ├─1 break
-        └─2 text "b|c}"
-    `,
-    `<p>{a<br>\nb|c}</p>`,
-    { hardLineBreaks: true },
-  ),
-);
+it('Nested ruby', () => {
+  const received = stringify(`{{a|b}|c}`, options);
+  const expected = `<p><ruby>{a<rt>b</rt></ruby>|c}</p>`;
+  expect(received).toBe(expected);
+});
+
+it('Ruby with newline', () => {
+  const received = stringify(`{a\nb|c}`, { ...options, hardLineBreaks: true });
+  const expected = `<p>{a<br>\nb|c}</p>`;
+  expect(received).toBe(expected);
+});