Why the Royal Flush Has Its Own Name
In ordinary high-hand poker, a straight flush is five consecutive cards of the same suit. A royal flush is the top possible version: the sequence runs from 10 up to ace. Its special name marks its place at the very top of the hand rankings; it is not a different kind of combination.
The Ace Sets the Boundary
The ace matters because it completes the highest straight. In many poker games, an ace can also count low in a sequence—A-2-3-4-5—but it cannot loop around from king back to 2. So a queen-king-ace-2-3 is not a straight, even if every card matches suit.
That boundary makes the royal flush easy to identify: the cards must be 10, jack, queen, king, and ace, all in one suit. Any other five-card same-suit sequence is still a straight flush, just not the royal one. When a royal flush appears, it wins against every ordinary poker hand because no higher straight flush is possible.
