Cotoyogi
Cotoyogi is the web crawler operated by ROIS-DS, a Japanese public research institution. It visits publicly accessible web pages and saves their content to create the datasets used to train Japanese AI models. If your site has Japanese-language content or targets the Japanese market, allowing it through may increase the chances of those models referencing your business. For English-language or local Western businesses, its effect on AI visibility is negligible.
- User-agent
CotoyogiCotoyogi/4.0- Does it respect robots.txt?
- Yes
- Official documentation
- https://ds.rois.ac.jp/en_center8/en_crawler/
How to allow it in your robots.txt
User-agent: Cotoyogi
Allow: /How to block it (not recommended)
User-agent: Cotoyogi
Disallow: /Frequently asked questions
Should I block Cotoyogi?
Only if you have a specific reason to. If your site is in English and targets a local or Western audience, blocking it makes little practical difference. If you have Japanese content or want to appear in Japanese AI tools, letting it crawl is the smarter move.
Does Cotoyogi affect my AI visibility?
Only in AI models trained on its datasets, which are primarily Japanese. It has no impact on ChatGPT, Gemini, Perplexity, or other mainstream Western AI tools your customers are likely using.
How can I tell if Cotoyogi is visiting my site?
Check your server access logs for requests where the user agent contains «Cotoyogi/4.0». Visits come from IPs in the range 157.1.136.4–157.1.136.11. If you are unsure where to find those logs, your hosting provider can point you in the right direction.