Five playing cards forming the poker royal flush hand. Green background. Green background. A royal (straight) flush is when you have 10-J-Q-K-A, all of the same suit. This is the hearts suit royal flush. It is the highest-ranking standard poker hand. In five-card poker, there are 4 royal flushes, one of each suit. The probability of this hand is almost improbable and equals about 0.0015%. Good luck to you!