Four cards only, no pairs, no matching suits — the lowest qualifying hand wins.
Button and blinds.
Four cards, three separate discard-and-replace draw rounds.
Small bet after the deal and the first draw, big bet after the last two.
Best four-card hand with no repeated rank or suit — the nuts is 4-3-2-A rainbow. Any qualifying four-card hand beats any non-qualifying three-card (or worse) hand.