Triple-range what?

Triple-range what?

Thursday, 5 May 2011

Dear Dr Tom

I hear people talking about triple range merges and stuff like that, but I don’t even know what a single range merge is. Help, please. Is poker passing me by?

Richard, London

Dear Richard,

Your standard theory says you bet the river when you are strong (for value) or weak (as a bluff) but never in between. Merging your range means betting an extra bunch of hands that are slightly weaker at the top and others that are slightly stronger at the bottom. Why would you do this? There are three reasons, only one of which is really interesting.
Reason 1: It doesn't make you money on the hand in question but it makes you more unpredictable (see “advertising” above).

Reason 2: Opponent either calls too much or folds too much, so you either extend your betting range at the top or bottom. This is hardly “merging” – just standard exploitation of opponent’s calling range.

Reason 3: To “value-bluff”. I wrote about value-bluffing back in 2008 before the term had been coined, and the best term I could come up with was “feckless” betting which the mag’s editor didn't like and changed to the insipid “unorthodox”. Value-bluff is a much better effort.

Here’s how it works. First you secretly merge your range at both ends but cunningly neglect to tell your opponent. He assumes you’re still polarised (standard river theory). Now imagine the following had comes up (merging works in less extreme cases but this hand makes the point well).

You and your opponent are alone in the blinds and reach a board of 8-8-9-9-2 rainbow. You hold 2-2 and bet the pot for a valuebluff. That means you’re hoping to make money as either a value bet or a bluff. Opponent doesn't put you on 2-2: he reckons you are either representing the 9 or you have it since, as the saying goes, “you never bet when only a better hand will call you”. If he decides you’re betting for value he has to fold everything from eights full down. If he decides you are bluffing he can call with Q-x. Now because you have no tells opponent must lose in the long run here. Why? With twos full of nines on this board, you’re in the top 17% of hands. If an opponent decides you want a call he reckons he needs a nine to carve up the pot. This means he will be calling 2% of the time (that’s how often he holds a nine) and folding a further 15% of the time when he holds a winner. Kerr-ching!

You usually make money when he thinks you’re value betting. What if opponent decides it’s a bluff? A queen puts him in the top 53% of hands. While he’s a small dog to a random hand, his assumption that you’re polarised means you must be unusually weak, so a queen means a call. Now, if his calling range is Q-x up, then – kerr-ching! – he will show a winner 17% of the time and a loser 36% of the time.

As for triple range merges, that sounds oxymoronic but don’t quote me, poker moves so fast these days, I blame the kids, etc, etc.


Tags: Dr Tom