The low count where the ace is 1 and straights and flushes do not count.
The best hand is 5-4-3-2-A. Compare the highest card of the five first, the lower hand wins, and a hand with a pair loses to any hand without one. Example. 7♥ 5♥ 4♥ 3♥ 2♥ is not a flush or a straight here, just a "7 low," and between 8-6-4-3-2 and 8-7-5-4-2 the 8s tie, so compare the next cards, 6 and 7: 8-6-4-3-2 wins. Used by Razz, A-5 Triple Draw, and the low half of Hi-Lo games (Stud 8, PLO8, O8, Big O).