I know. Everyone who has a blue cat thinks they have a Russian Blue. No, they don't. They have a DSH. I have DSH cats, but I also have Russian Blues & Russian Blacks. The Russians are a very special breed, but so are moggies.
I know some confuse British Short Hairs that are "blue" but have a roundish head .Russian Blues have more pointed features and lighter body type.I got purebred/registered Eva Blue from the woman that literally wrote the book on the subject Ingaborg Urcia from Cheney Washington before she passed.Got all the breeding papers w/ bloodlines etc.
She closed her cattery and Eva was her own house cat. Eva Blue was 5 and then lived with me to age 18. Loved the sun & heat vents. Slept many hours in my lap. 100% indoors..Agree w/ above comment about temperment. Amazing breed.