From Zero to One Mitsui Chemicals creates countless futures.｜MITSUI CHEMICALS,INC.

三井化学株式会社 | 三井化学株式会社

VISION 2030 | 三井化学株式会社

MITSUI CHEMICALS, INC. | MITSUI CHEMICALS, INC.

MOLp® | そざいの魅力ラボ

ゼロからイチへ 三井化学は、無数の未来を拓いていきます。｜三井化学株式会社

Every page should have a clearly defined heading, known as a "H1" (Heading 1).

A `H1` is the main heading of the page. It helps accessibility by allowing uses to
skip to the main content of the page. It helps all users identify what the page is about. 
It helps SEO by giving special emphasis to the topic of the page.

It is not enough to simply include large text. Headings must be coded 
[semantically](https://html.com/semantic-markup/) as `<h1>` tags, like so:

```html
<h1>This is a heading</h1>
```

Note that headings must contain some machine readable text to be considered valid. 
For example, this heading is not valid:

```html
<h1>
    <img src="company-logo.png">
</h1>
``` 

But with the addition of `alt` text, this heading is valid:

```html
<h1>
    <img src="company-logo.png" alt="About Company Inc.">
</h1>
``` 

Generally we recommend you just use plain text for your headings.
See [Technique H42](https://www.w3.org/TR/WCAG20-TECHS/H42) for more details.

missing-h1

December 2025

November 2025

Mitsui Chemicals Inc

Title / URL	Issues
From Zero to One Mitsui Chemicals creates countless futures.｜MITSUI CHEMICALS,INC.jp.mitsuichemicals.com/en/corporate/brand/	1
三井化学株式会社 \| 三井化学株式会社jp.mitsuichemicals.com/jp/index.htm	1
VISION 2030 \| 三井化学株式会社jp.mitsuichemicals.com/jp/corporate/vision/index.htm	1
MITSUI CHEMICALS, INC. \| MITSUI CHEMICALS, INC.jp.mitsuichemicals.com/en/index.htm	1
MOLp® \| そざいの魅力ラボjp.mitsuichemicals.com/jp/molp/index.htm	1
ゼロからイチへ三井化学は、無数の未来を拓いていきます。｜三井化学株式会社jp.mitsuichemicals.com/jp/corporate/brand/index.htm	1

Ensure every page contains a top-level heading

Mitsui Chemicals Inc

Where this issue has occurred