Quote 1
In his will Sam Westing implied (he did not state, he implied) that (1) he was murdered, (2) the murderer was one of the heirs, (3) he alone knew the name of the murderer, and (4) the name of the murderer was the answer to the game. (8.74-75)
Here Judge Ford does a great job of close reading the will, reminding herself (and by extension, the readers) exactly what Westing does and doesn't say in the will, versus what the will seems to be conveying to the other players/readers. The key here is in her repeated use of the word "implied," which puts her on a path towards thinking what else the will might be saying – someone else could be in danger.
Quote 2
The queen's sacrifice! The famous Westing trap. Judge Ford was certain now, but there were still too many unanswered questions. "I'm afraid greed got the best of you, Theo. By taking white's queen you were tricked into opening your defense. I know, I've lost a few games that way myself." (25.27)
Theo's loss in the actual chess game, which he played against an anonymous opponent, mirrors the heirs' loss in the game for Westing's fortune. He loses this game just as Judge Ford lost her games so many years ago, and just as the heirs have all lost the game set forth in the will. There's something about thinking a win's coming that makes players (in chess or in this game) overconfident. The players, and Theo, sacrificed their queens (Crow) just as Westing knew they would.
Quote 3
"I barely saw Mrs. Westing. Violet was a few years younger than I, doll-like and delicate. She was not allowed to play with other children. Especially the skinny, long-legged, black daughter of the servants." (21.33)
In a way, society restricts people in each of its class settings. It's easy to sympathize with the judge, who had to fight against prejudice as a servants' daughter, and has worked very hard to become upwardly mobile. But in a way, can't we also sympathize with Violet, who doesn't get to play? It seems particularly unfair that the daughter of a chess master doesn't get to play games with other people; what's more, it's even odder when we think about how Westing played chess with the judge when she was a young girl.