Ron hates Occlumency.
He finds no sense in the meditation exercises that have him struggling to visualize a stupid candle in a 'void' he doesn't even understand the meaning of.
He doesn't get how 'clearing the mind' could be possible and doesn't see the point in finding one's mindscape anyway.
When they move onto the building of defences and the book Hermione is devoutly reading to them starts talking about walls and fortifications and surrounding one's mind with shields, he gets bored within ten minutes and lets his mind drift back to the last challenging chess match against that Ravenclaw bloke who can really make him work for his victories.
He feels vaguely guilty and uncomfortable, but not enough to go back to the exercise he is supposed to practice.
Until Hermione startles him by rather suddenly insisting they share their progress and describe their mindscapes and caught off guard, he blurts out 'chessboard', because that is what he's thinking about.
He expects reproach and is surprised when instead, Hermione's eyes light up with admiration.
'That's brilliant', she says, 'very original.'
She prattles on about using a game of chess to trap the invaders and slow them down, she expands on hiding memories inside the pieces, the less important in the pawns, the most precious in the king, she recalls McGonagall's giant chessboard back in their first year.
Ron listens in fascination.
This he can understand.
This he can do.
He's good enough that he can adapt his strategy as needed, too, protecting now the knights, then the rooks, sacrificing a bishop to guard the queen or vice versa, in relation to what his challenger – his attacker – is after, to what he can afford to expose and what he must protect.
His mind is a chessboard, and Ron knows he is unbeatable at his game.
Disclaimer: No copyright infringement is intended.
