Yandex

Yandex is the leading search engine across Russian-speaking markets, with an index and ranking model built specifically around Russian morphology.

It is more than search: maps, taxi, mail, cloud storage and a marketplace share the same account, so for many users it functions as a full ecosystem rather than a single tool.

If you publish Russian-language content, Yandex is worth treating as a separate optimization target — its ranking signals differ from Google's, and its Webmaster console reports crawl and index status that Google's tools will not show you.