<!DOCTYPE HTML>
<html>
<head>
    <meta charset="utf-8">
    <style>
            body { writing-mode: vertical-rl; }
            .underline { text-decoration: underline; }
            .overline { text-decoration: overline; }
    </style>
</head>
<body lang="en">
    <div>In vertical writing mode with lang=ja, default overline will be same as underline (lang=en). However, when we set text-underline-position to "under left" it should be shifted.</div>
    <div class="underline">サンプル</div>
    <div class="underline">サンプル</div>
</body>
</html>