I just don't see how the description of this matches with the title [a chess move] and the tags saying how it relates to chess. It is just a metaphor, comparing the events with the foresight necessary for chess games?

Have you read it? There are a lot of chess references:

The main characters each have ranks (king, queen, bishop, knight, or rook) and there are two sides (white and black) as well as two "worlds" ("light square" and "dark square"). "En passant" is the name of the white side, opposing the black side "Valde".

Thanks. I hadn't read it, generally don't start a manga when i'm confused as to what it's about unless it's recommended.

Thanks again.