Definition of "main line"

In that game, Carlsen sidestepped the main line of the Berlin Defense with 4 d4, hoping to unsettle Karjakin. That did not work, and chances were equal for most of the game.

2012 July 15, Dylan Loeb Mcclain, “Chess: Fischer and Spassky, Looking Back”, in The New York Times‎, archived from the original on 2022-06-20

8.Qd2 is the old main line of the Poisoned Pawn from the days of Fischer and Kasparov.

2015 May 6, Malcolm Pein, “Chess prodigy Wei Yi, 15, tops the chart”, in The Daily Telegraph‎, archived from the original on 2020-11-08

Adams, the No1 seed in the Isle of Man, has always favoured 3 Nd2 against the French and, when his Polish opponent, below, followed a main line, Adams was very willing to go along.

2015 October 9, Leonard Barden, “Sergey Karjakin and Peter Svidler blunder through Baku World Cup final”, in The Guardian‎, archived from the original on 2016-09-11

Gavin Johns, chairman of the Swanage Railway Trust, said: "I would like to thank our stakeholders for their far-sighted investment of £5.5 million to re-connect Swanage and Corfe Castle with the main line, which included £1.8m from the Government's coastal communities fund, so we could restore our 1950s heritage diesel trains for running on the main line."

2023 March 22, “Tickets now on sale as trial Swanage service finally gets green light”, in RAIL, number 979, page 25

Caruana chose the Petroff 2 Nf3 Nf6, which used to be the weapon of choice for players aiming for a half point as Black, was relegated for some years due to the popularity of the Berlin 1 e4 e5 2 Nf3 Nc6 3 Bb5 Nf6, but has returned to favour as the main line Berlin with an early queen swap has been outmoded by 4 d3.

2018 January 19, Leonard Barden, “Chess: Magnus Carlsen falls away from leading pack at Wijk aan Zee”, in The Guardian‎, archived from the original on 2022-11-29