Boris Romanovich Rotenberg Boris Romanovich Rotenberg Boris Romanovich Rotenberg (, born in Leningrad on 3 January 1957) is a Russian business man and oligarch. He is co-owner (with his brother Arkady Rotenberg) of the SGM (StroyGazMontazh) group, the largest construction company for gas pipelines and electrical power supply lines in Russia. He was listed by Forbes as Russia's 69th wealthiest person in 2016 with a net worth of $1.07 billion. He is considered a close confidant of president Vladimir Putin. Rotenberg was very involved in martial arts between 1968 and 1978, particularly judo. He trained alongside Vladimir Putin and won several awards for
Sparring striking an inappropriate area or stepping out of the ring. Sparring in a grappling art such as judo might begin with the partners holding one another and end if they separate. The organization of sparring matches also varies; if the participants know each other well and are friendly, it may be sufficient for them to simply play, without rules, referee, or timer. If the sparring is between strangers, there is some emotional tension, or if the sparring is being evaluated, it may be appropriate to introduce formal rules and have an experienced martial artist supervise or referee the match. In