Going from Russian to Japanese (ζ₯ζ¬θͺ) has a composite linguistic distance of 88% (heuristic estimate). Below is the dimension-by-dimension breakdown.
Shared vocabulary, cognates, and loanwords.
Morphology, syntax, word order, cases.
Shared sounds and phoneme inventory.
Cyrillic β Japanese
Indo-European β Japonic
The 5 languages with the lowest linguistic distance from Russian:
A quick 3-question check between Russian and Japanese. No signup.