As in all lowball games, pairs and trips are bad: that is, any hand with no pair defeats any hand with a pair; one pair hands defeat two pair or trips, etc. No-pair hands are compared starting with the highest ranking card, just as in high poker, except that the High hand loses. In ace-to-six low, Straightss and Flusheses count for high (and are therefore bad), and aces play as the lowest card.
For example, the hand 8-5-4-3-2 defeats 9-7-6-4-3, because eight-high is lower than nine-high. The hand 7-6-5-4-2 defeats both, because seven-high is lower still. The hand 7-6-5-4-3 would lose, because it is a straight. Aces are low, so 8-5-4-3-A defeats 8-5-4-3-2. Also, A-A-9-5-3 (a pair of aces) defeats 2-2-5-4-3 (a pair of deuces), but both of those would lose to any no-pair hand such as K-J-8-6-4. In the rare event that hands with pairs tie, kickers are used just as in high poker (but reversed): 3-3-6-4-2 defeats 3-3-6-5-A.
It is called ace-to-six low because the best possible hand is 6-4-3-2-A, followed by 6-5-3-2-A, 6-5-4-2-A, 6-5-4-3-A, 7-4-3-2-A, 7-5-3-2-A, etc.
When speaking, low hands are referred to by their highest ranking card or cards. Any nine-high hand can be called "a nine", and is defeated by any "eight". Two cards are frequently used: the hand 8-6-5-4-2 can be called "an eight-six" and will defeat "an eight-seven" such as 8-7-5-4-A.
A Wild card plays as whatever rank would make the lowest hand. Thus, in 6-5-Joker-2-A, the joker plays as a 3, while in Joker-5-4-3-2 it would play as a 7 (an ace or six would make a straight).
High-low split games with ace-to-six low are usually played with a Declaration.