Parity the most important part of the strategy. In short, the concept of parity is about getting the last move in every empty region in the end-game, giving oneself a better chance to increase the number of stable discs. The concept of parity led to a change in the perception of the game, as it led to distinct strategies for playing black and white.
It forced black to play more aggressive moves and gave white the opportunity to stay calm and focus on keeping the parity. As a result the opening books and mid-game were focused on black being the "attacker" and white being the "defender". The concept of parity also controls how edge positions are played and how edges interact.