From the introduction:
It’s 1877, and you’ve arrived in the ghost town of La Paz in the Arizona Territory. You accepted an invitation to join an exclusive competition with some of the fastest and deadliest gunfighters on the frontier. The stakes are high, and the danger is palpable. Whether you’re participating for the glory, the riches, or some personal vendetta, you’re fixin’ to test your mettle in a tournament where one winner takes all—and the losers might find themselves taking a mighty long dirt nap.
Sole Survivor is a tourney of one-against-one Showdowns—one of Savage Sidewinder’s Setting Rules. Don’t fret, we jaw plenty about how the Showdown works in Sole Survivor.
You need a Judge (that's GM to city slickers) and up to eight players to play Sole Survivor.…How the tourney is organized is up to the Judge, from a quick single-elimination affair to an extended double-elimination event.