The Sämisch Variation is 3.Nc3 Bg7 4.e4 d6 5.f3. It is named after Friedrich Sämisch, who developed the system in the 1920s. This often leads to very sharp play with the players castling on opposite wings and attacking each other's kings, as in the Bagirov–Gufeld game given below, though it may also give rise to heavyweight positional struggles. Black has a variety of pawn breaks, such as ...e5, ...c5 and ...b5 (prepared by ...c6 and/or ...a6). This can transpose to the Modern Benoni after 5...0-0 6.Bg5 c5 7.d5 e6. World champions Mikhail Botvinnik, Mikhail Tal, Tigran Petrosian, Boris Spassky, Anatoly Karpov and Garry Kasparov have all played this variation. This line defends the e4-pawn to create a secure centre and enables White to begin an attack kingside with Be3, Qd2, Bh6, g2–g4 and h2–h4. It allows placement of a bishop on e3 without allowing ...Ng4; however, its drawback is that it deprives the knight on g1 of its most natural square, thus impeding development of the kingside. Black can strike for the centre as previously mentioned or delay with 6...Nc6, 7...a6 and 8...Rb8 so that Black can play ...b7–b5 to open lines on the queenside.