 Complete the following phrase:  The Berlin Defence, 3...Nf6, has long had a reputation for solidity and drawishness and is commonly referred to as the Berlin Wall. The Berlin Defence was played in the late 19th century and early 20th century by Emanuel Lasker and others, who typically answered 4.0-0 with 4...d6 in the style of the Steinitz Defence. This approach ultimately fell out of favour, as had the old form of the Steinitz, due to its passivity, and the entire variation became rare. Arthur Bisguier played the Berlin for decades, but always chose the variation 4.0-0 Nxe4. Ever since Vladimir Kramnik successfully used the line as a against Garry Kasparov in their 