The term CHIEF RUSSIA is composed of two crossword solutions, OMSK and TSAR. OMSK is a city in Russia located in the southwestern part of Siberia on the banks of the Irtysh River. It is the administrative center of Omsk Oblast and the second largest city in Siberia after Novosibirsk. TSAR is a title used to refer to the autocratic rulers of Russia from 1547 to 1917. It was the highest rank in the Russian Empire and was equivalent to an emperor.