ステータスコード404(見つかりません)
HTTP Status Code 404 indicates that the server could not find the requested webpage. While occasional 404s are normal, a high number of 404 errors creates poor user experience and wastes the "crawl budget" of search engine bots, preventing them from indexing important content.
The International SEO Silent Killer
In multilingual sites, 404s often occur when a language switcher links to a page that hasn't been translated yet. User clicks "French" → gets 404 → leaves frustrated. Or worse: Google crawls the French sitemap, finds 1,000 URLs that return 404, and marks your site as low-quality. The solution: either don't link to untranslated pages, or implement "soft 404 prevention" by redirecting to the nearest available parent page with a message like "This page isn't available in French yet, here's the category page." Monitoring 404s in Google Search Console should be a weekly task for international sites.
Hard 404 vs. Soft 404
現実世界の影響
E-commerce site links to 500 untranslated German product pages
Language switcher generates 500 404 errors
Google flags site quality issue, rankings drop 30%
Hide language switcher for untranslated pages
Zero 404s, users only see available content
Site quality score improves, rankings recover