By the middle of Act 5, Scene 1, Prospero has worked his magic to win back his dukedom and he has also orchestrated the marriage of Miranda and Prince Ferdinand, who everyone thinks is dead thanks to Prospero. Still, Prospero's got one more trick up his sleeve. In the middle of the scene, Prospero gathers everyone around and dramatically draws back a curtain to reveal his virginal daughter and Ferdinand...playing a game of chess. Surprise!
It looks like Ferdinand has made good on his promise to keep his hands to himself until his wedding night, wouldn't you say? As it turns out, the conversation going on between Miranda and Ferdinand is as G-rated as the action. Miranda bats her eyelashes and says something cute ("Sweet lord, you play me false") and Ferdinand promises that he'd never do such a thing (5.1.1). So, it seems like chess is being used here as a metaphor for romantic pursuits or, the kinds of teasing little "games" played by people who are in love.
We really want to believe Ferdinand when he says he'd never cheat (it wouldn't bode well for the couple's marriage), but we can't say the same thing about the parents of this sweet couple. Hmm. Is Shakespeare trying to tell us something?
Let's think about this. The goal of a chess game is to capture your opponent's king by strategically placing him in a position from which he can't move. Gee. That sounds kind of familiar. Where have we seen this kind of game before? Oh, we know! This is exactly what's been going on between Prospero and Alonso ever since the King of Naples allowed Antonio to steal Prospero's dukedom. In the end, Prospero has ultimately won this little game by backing Alonso into a corner from which the king cannot move. Check mate. Game over.