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View Full Version : Manipulating your opponent's ranges


pergesu
09-06-2005, 05:15 PM
This is an idea I've had for a while, and I think when applied it can help increase your ROI quite a bit.

Let me start off by stating a few assumptions that are well-known, but that new players often forget.

1. Poker tournaments are a balance of risk and reward. Unlike in a cash game, where you should seize every +EV situation, you should often pass on marginally +EV spots in a tourney. This is because when you're out of chips, you're out of the tourney, and can't take advantage of greater +EV situations later on. An example is calling an all-in with a medium pair. The reward is pretty high - you double up - but the risk is as well, leaving you out of the tourney nearly half the time.

2. Later on in the tourney you should be willing to assume more risk, as long as the reward is correspondingly high.

Those are basic ideas that all tournament players should be familiar with. Now we can get into more interesting stuff.

Everyone knows that different hands have different values compared to other hands. You're a 60/40 favorite, it's a coin flip, etc. This is important in determining whether it's mathematically correct to either raise or call an all-in bet. Another imporant idea is how your hand's value changes based on how your opponent's range changes. Some hands gain value when your opponent widens his range, and others lose value. In particular, mid-high pairs (JJ, TT) gain value, and unpaired high-card hands lose value.

The below examples come from TPFAP pp 115-117.

For the first example, we'll say you have a pair of jacks. If you play your hand one way, your opponent will be willing to put all his chips in with 99+ and AK. If you play it differently, his range tightens to QQ+ and AKs. Clearly it is to your benefit to play the first way, because it adds two hands that you're a significant favorite over to his range.

If you have AK in the same hand though, it's to your detriment to play in such a way that he expands his range. This is because you add a few hands that are a favorite over you, and you get called more often.

This leads us to a rather obvious principle. If your hand is a large favorite over the hands below it, you should seek to maximize your opponent's range. If your hand is a dog or only a moderate favorite over the hands below it, you should seek to minimize your opponent's range.

All of this has to do with balancing risk and reward. If I can get a player to put his stack in with an underpair to my pair, I achieve great reward (his stack) with minimal risk (I win about 80% of the time). Thus I would want him to call with as many pairs as possible. However if I hold AK, I don't want him calling with pairs, because now I'm a dog to more hands.

The very important part is how you apply it. Here are some basic guidelines for early on in a tournament. These are if you're up against a decent opponent.
1. Play unpaired high-card hands aggressively preflop. Be willing to raise all-in, but far less willing to call an all-in.
2. Play mid-high pairs more passively preflop. Be willing to call an all-in bet.

The reason for this is that when you play your hand aggressively, your opponent tightens his range up. You want this when you hold a hand like AK because you'd prefer to take down the pot than get called by a small pocket pair. The opposite is true when you have a pair yourself - taking down the pot is fine, but you'd love to get called by a smaller pair. Playing your hand weakly also entices your opponent to try to push you off with a weaker hand, which is what you want.

As with everything else in poker, you can't just use those without thinking about your opponent. In fact, against truly bad opponents I think the total opposite is true. You should play your pairs aggressively, because people will often limp with a small pocket pair and then call an all-in bet. They're also not likely to shove their chips in hoping to push you off a hand, so you don't get the opportunity to trap with an overpair. At the same time, being aggressive with hands like AK is a bad idea because you get your chips in as a dog or a small favorite, instead of giving yourself the opportunity to see the flop and outplay your opponent.

Really, in early play I don't think you should be very aggressive with AK preflop, because the vast majority of opponents at the lower limits fall into the second strategy group.

I think a lot of this seems pretty obvious when you read it, but most people don't really think about it or apply it when playing. I also think that a lot of this changes later on in the tourney, because you need to be able to accept more risk. That's for a different thread/reply, I guess.