The "hedgehog" structure is a very resistant structure that also offers many possibilities for active play. It is not the specific variations that are important, but the knowledge of the typical ideas and plans. Dutch coach Herman Grooten teaches this in his Fritztrainer course "Key concepts of Chess - The Hedgehog". Philipp Hillebrand had a look at the course.
A Russian chess master has actually been banned by the International Chess Federation, Chess.com, as well as the Grand Chess Tour for making declarations extolling his support of Russian President Vladimir Putin. Russian grand master Sergey Karjakin, 32, is banned by the chess authorities for 6 months– suggesting that he will miss the Candidates Tournament| USSA News