Russian Morse extends international Morse with codes for the Cyrillic letters that don't appear in Latin script. Most Cyrillic letters that share a Latin equivalent use the same Morse pattern; the rest were assigned new patterns.
The Cyrillic Morse table was standardized in the late 19th century during the rapid expansion of the Russian telegraph network. It served not just Russian but also Bulgarian, Ukrainian, Serbian, and other Cyrillic-script languages with minor local additions.
Russian amateur radio (RAEM, the Russian DX Association, and many others) still uses Cyrillic Morse for native-language QSOs. Bulgarian and Ukrainian operators use a similar table with a few letter substitutions.
Most letters share the same code (А = .- like A, Б = -... like B). The differences are in letters specific to Cyrillic: Г, Ж, З, Й, Ц, Ч, Ш, Щ, Ы, Ь, Э, Ю, Я each have unique codes.
Mostly. The Cyrillic Morse alphabet works for all major Cyrillic-script languages, with minor adjustments for letters not used in Russian (Ї, Є in Ukrainian; Ѫ historically in Bulgarian).
Only by transliterating to Latin first. Cyrillic letters with no Latin equivalent (Ы, Ъ, Я, Ю, Ш, Щ) need the Cyrillic codes. there's no way to spell them with International Morse alone.
Explore all Morse code variants → Morse Code Variants Around the World