I've been looking for information about a Russian relative called Izia Rahtanov (Rahtanov Isai Abramovich), we have no details.
He was born in Harbin, 1907. He spent his childhood in China. In 1923 he arrived in the USSR. He studied at the Leningrad Institute of Art History. Began to publish since 1929. He died in 1979 Moscow, I guess.
His mother was Klara Vladimirovna Kofman from Odessa (Russia) His father (Abram) Rahtanov.