The hedgehog system is characterized by a row of Black pawns on the 6-th rank: a6, b6, d6, e6 and alternatively g6 with open c-file, against white pawns c4 and e4. When playing the hedgehog, one suffers from the lack of space - all Black pieces are placed on the three last ranks but the position has no weaknesses. Experience has shown that it's very hard to crack hedgehog positions.