(After googling, it turned out to be a blog post: https://observer.com/2016/01/your-life-is-tetris-stop-playin...)
The metaphor assumes that life is a game in which there are a finite number of moves and someone is playing to win… chess isn’t remotely a workable metaphor for life.
If I had so sum it up (always hard with an allegory):
Developing superhuman AI is a game you can only play once and can expect to lose without ever having a good understanding of how, why or even when you lost.
The suggestion is (like in the movie Wargames) that the best move is not to play.
I'd say the child in the story is mankind. Developing strong AI is the game. It's a game we can expect to lose.
Now, it could be that “you” is Homo Not So Sapiens and the child is Homo Antesingularity… but even then I think you’re stretching it past its breaking points.
But that's not right. Stockfish is superhumanly intelligent at playing chess but it is not the result of a single match between its creator and itself. Humans played chess against computers over and over, for decades, and the "superintelligence" level was seen coming a mile off. Moreover it was never dangerous and those AI techniques never led to a general intelligence.
This is the problem with AI doomers like Yudkowsky. They use rhetorical skill to make clever sounding arguments that contain fallacies, and hope you won't notice. The assumption you can only "play once" is a wild one and thrown in at the end with absolutely nothing earlier in the story supporting it or backing it up.
In any cartoon you choose which features to keep and emphasize and which features to leave out.
Chess is a game of perfect potential knowledge - where the only limit to seeing is your own ability.
What's nice about chess is the "if-I-do-this,-what-happens-in response" kind of thinking it instills.