MD:
A hand with showdown value is any hand that can win at showdown given the action in the hand.
"Showdown value," describes the full range of hands you could win with at showdown, from having the nuts to having a high card hand that has no value except as a bluff catcher to lower high card hands.
Most of poker is about quantifying the amount of showdown value your hand has. Phrased differently, we analyze the strength of our hand as compared to the villain's range to have taken the actions he has taken so far in the hand.
So, for example, suppose you have A
J
in MP1. You raise preflop. The button calls, everybody else folds.
The flop comes down Q
T
7
.
You bet, the villain calls.
Turn: 2
You bet, villain calls.
River: 2
So now the question is whether your hand has showdown value. What hands are you beating, if any? What hands are you ahead of, if any? Is my hand worth more money at showdown (how much of his range can I beat if we showdown) versus how many of his hands can I beat by betting?
You'd ask yourself the same question if you had AT here.
You'd actually ask yourself the same question with QQ, but the answer would be obvious.
What this discussion highlights is that we usually use the term "showdown value" as a slang reference to hands that are ahead of some of the villain's range and behind some of his range. But we are always trying to figure out whether we are ahead of enough of his range to want to get the hand to showdown, or behind so much of his range that we are so likely to lose at showdown that we should either fold or bluff.