It's like a war. The black pieces and the white marching across the battlefield to engage in fights, one side only winning when they managed to corner the opposing side's king. How it captured the interest of two people of opposing sides will remain a curiosity.
One side, the white, just, loyal and 'good' side used it as an opportunity to relax after missions, a much calmer way than that of his teammates. While they preferred the high-flying and risk-taking involved in extreme sports, he preferred to sit in front of a computer, matching his wits against it in a battle of logic and patience.
The other, the black, conniving, deceitful and 'evil' side preferred to use it as a training exercise in deploying troops, testing out new pathways and configurations in order to create a victory for his side. However, for him, there was always one unknown which was always present in the equation and which could never be worked out.
Those two words, one person, linked together the two opposing forces, one determined to keep him safe, the other preoccupied with capturing, studying and killing him. Whichever side won the battle depended on a roll of the die, the turning of a card, the movement of a single pawn.