In Seven-Card Stud Hi/Lo it is possible to deduce whether your opponent is likely to have made a low or not by looking at his up cards. Unless he has two or more unduplicated low cards on his board, he cannot possibly have made any kind of low. On the other hand, if his board comprises four different up cards then he has probably hit a low of some sort. In that case he would only require that one of his three down cards be an unduplicated low card in order to complete a low hand.

 Down Cards Up Cards

With only one unduplicated qualifying low card among his up cards, it is impossible for your opponent to make a low hand here. He requires five different low cards ranked Eight or below.

 Down Cards Up Cards

Here the best low that your opponent can make is an Eight-low. There are only two low cards in his up cards, so he must use both of them in any low that he might make (if indeed he has one at all). His only possible low hand is therefore the Eight-low 8-?-?-?-A, where each ? represents an unpaired card from Seven to Deuce.