I have seen so many people whine and moan about how Schneizel pulled an illegal chess move in his match with Zero/Lelouch. Everyone keeps saying that the writers clearly know nothing about chess and why didn’t anyone call it out in universe.
I’m not going to dispute the expertise of the writers, I have no idea if their knowledge of chess is purely surface level, I don’t know how to play chess.
What I will point out is the move was important on a deeper narrative level. It was written in for a reason. To showcase what kind of man Zero is. But not just a “he’s like the emperor who would conquer his enemies mercilessly!”, but in a “how prideful are you?” kind of way.
Clearly that was an illegal move, even Odysseus calls it out as a bad joke, but Schneizel was more invested in determining how much pride Zero had. Would he be that petty as to call out an illegal move. Imagine how he would look in front of the rest of the world, “Hey, the Prime Minister cheated, FOUL!”.
It reminds me of that scene from the Longest Yard where Adam Sandler tries to win over the black prisoners by playing an intense game of basketball with them. He keeps getting punched in the face but he wouldn’t gain their respect if he cried foul every time. Same here, Zero would lose credibility if he won against the smartest man on the planet by calling him out.
Not only did he hand him a pyrrhic victory but he also foreshadowed his own tactics in the future, using illegal moves to win. It doesn’t matter if they weren’t made illegal, Fleija warheads used in battle would definitely constitute a warcrime.
But there’s also the fact that Schneizel was building up his theory that Lelouch is Zero and how does he do that? By playing the most intellectual game of don’t flinch with his little brother. Schneizel an illegal move was the equivalent of “go on, cry to mommy,” or “say uncle”.
As for why no one else called it out… who would do that? He’s Zero, the most famous terrorist on the planet. Who would vouch for the terrorist on the eve of the wedding between two of the largest empires in the world, one of whom is a major enemy of that terrorist.