the.com/brass ring

The prize you grab by leaning dangerously far off a moving carousel.

means The symbol of a top prize or opportunity, especially one you have to take a risk or act fast to seize.

from Comes from old carousel rides, where a mechanical arm dispensed metal rings for riders to grab as they passed — most were iron, but one was brass, and snagging it won you a free ride. The literal game faded, but 'grab the brass ring' endured as shorthand for chasing the one grab-able shot at success.

origin
Real rings on carousels, grab one, win a free ride
irony
Usually iron, painted to look valuable
meaning shift
Now means any big opportunistic grab, no horse required
idiom cousin
Related to go for broke, not go for gold
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