Bet/folding versus check/calling

Getting better at poker is often - mostly - a slow and gradual process. Some steps are small and some are big. I was recently reminded of one of my big steps; a very "aha!" moment I had: When I realized why sometimes bet/folding the river was better than check/calling.

On the surface, it's counterintuitive. Let's say that I can either put in $20 myself on the river, but fold if my opponent raises, or I can check and call $20 if he bets. "Either way," I told myself, "I've put in $20, but in the second case I get to see a showdown. How could the first option possibly be better?"

It can be, and it often is. It all comes down to ranges. I expertly made a little illustration to help, well, illustrate the point (click on it to see a larger version):

The bar represents, from left to right, our opponent's range. The farther to the right, the stronger his hand. On a A64-K-J board, for instance, QT (the nuts) would be all the way to the right, and 75 would be all the way to the left. The nuts vs. absolute trash. Let's keep the A64-K-J example and run with it for awhile. And let's give ourselves A-K.

The colors represent what the player is likely to do and the respective outcome for us. In the first bar, we bet out. If we ignore our opponent's trash in the beginning, we see that there's a pretty wide green bar in the middle. That green is the range that he's willing to call with that we beat. It includes hands like AQ, perhaps KJ and probably other top-pair type hands. Farther to the right, we have the red hands - the ones that beat us. This consists of sets and straights. He will most likely raise any hand that beats us.

If you notice the small red part in the beginning, it's because I'm allowing for my opponent to sometimes bluff raise us, and for all intents and purposes, we can say that he will do that with the very worst of his hands. Maybe 5-7, that missed its open-ended straight draw, will take a stab on the river.

Here's what to take home from this illustration: The green parts are where we make a bet. The red parts are where we lose a bet. The idea is to maximize the size of GREEN minus RED.

... and that brings us to the second bar, where we instead of betting out decide to check and call. This time, our opponent's bluffs (at the very left of his range) will be called and are therefore no longer red; they're green. We make money when he bluffs. But then comes an alarmingly long stretch of black; black meaning that we didn't make anything. He just checked behind and we won the pot with the best hand. Most players are careful on the river; they don't want to risk more money with a marginal hand. They might call to see if you're bluffing or just to see if their hand was good enough, but if they could choose, they'd prefer not to put money in. That's where the black stretch comes from.

Then there's some green stretch farther to the right; his stronger hands that you can still beat. Ace-jack comes to mind. And of course, all the way to the right are the same monsters as in the first bar, that he will surely bet for value when you check to him. Again, they're red, and again, you lost $20 to them.

But, and here's the whole point, note how much bigger the GREEN minus RED is in the top bar.

This is why bet/folding is such a powerful weapon. It forces opponents to pay to see a showdown when they'd rather not, and it's a hugely profitable strategy as long as this particular player isn't prone to bluffing too much - thus making the red stretch on the left bigger - compared to how much he's calling - thus shrinking his green stretch in the middle.

Like I said, this was one of my greatest "aha!"-moments.