Protecting Poker Hands on the Turn

An earlier post offered some suggestions on playing a vulnerable poker hand, like top pair, on the flop. What about protecting it on the turn?

In other words this card has not completed any obvious flush or straight and you reckon still to be ahead. Standard wisdom has it that a bet of half the pot here will price any opponent out of the hand but implied odds suggest this is not so.

To keep the maths relatively simple, suppose there had been 4 big blinds (BB) in the pot on the flop and one opponent remained. This seems like a pretty average scenario. Now, on the turn, there are 12 BBs: the original pot; your bet; and the opponent’s call. If you bet half of this (6BB) and your opponent calls again, the pot will have 24BB on the river.

Then, disaster. The river card hits: it seems to complete a flush or an obvious straight. Your opponent bets to represent this. Do you call or fold? It depends on how much he bets.

Assume that he was drawing to a flush and so had a 4-1 chance of completing on the river. Four times out of five he will lose his turn bet of 6BB for a net deficit of 24BB. The fifth time needs to more than compensate for this. It’s not hard: 18BB already come from the pot and your bet on the turn. Your opponent only needs 6 more to break even. This is a quarter of the pot at the river.

If he bets this or less, you should call. He’ll never make any money that way, which implies that you'll never lose any. In fact, you'll come out ahead by occasionally calling pure bluffs or hands where the bettor genuinely thinks he is ahead but you have him beat.

Unfortunately the river bet is rarely this small. You then have to apply a sliding scale to decide whether to call or not. The bigger the bet, the less inclined you should be and the better hand you will need. It gets a little complicated.

Matters are so much simpler if you bet around the pot on the turn. Yes, we've gone back there with 12BB in the pot. You bet around 12 yourself and your opponent calls. This makes 36BB at the river, when the same disaster strikes. But now your opponent needs to make 48BB to justify losing 12BB four times. 24BB come from the pot and your bet at the turn, so he needs to get another 24BB.

This is a much bigger gamble on the river, fully 2/3 of the pot. Now you can call any bet smaller than this and come out ahead. In fact, again taking bluffs and misjudgements into account, you could probably call near pot-size bets most of the time.

If your opponent were drawing to an open-ended straight, at slightly better than 5-1 odds, he would need nearly 60BB, which is a pot-sized bet. And with any kind of hand (say you’d improved to two pair or a set) you could probably call any bet – with your entire stack if necessary.

Betting aggressively raises the bar, quite a lot, at which you have to make calling decisions. Note that if you’ve identified an opponent who never bluffs, you simply don't call apparent made hands, thereby removing any possible gain he could make from this play. And don't forget to bet for value yourself against a known fish but beware of likely slow-players.

But they're a whole article to themselves.

Another Environmental Yardstick: the McFarthest Spot

This is brilliant: check out the map in particular from what I think is a photography blog in the US, but the words will make you laugh too.

The Berlin Wall for Wildlife

And it's being built in the US of all places. Or not so surprisingly seeing as it's a legacy of the Bush era. Let's hope that Mr Obama can find time from fixing all the old fart's other fuck-ups to get round to this one. The poor chap has his work cut out! An excellent US nature blog reveals all.

Long-Billed Dowitcher, Chew Valley

This American wader just happened to me. BirdGuides had listed it a few days back but I'd thought no more about it until I stopped at Herriott's Bridge this afternoon as part of my standard route round the lake. I was only in the area looking at a room to rent in Chew Stoke, which pretty much has to be a birder’s dream. Fingers crossed on that one.

A gaggle of telescopes at the lay-by told me something was up, so I hauled mine out of the boot and joined them. I picked up the muttering of “long-billed dowitcher” and then remembered the earlier report.

Among half-a-dozen snipe the stranger was easy to separate. But was it a dowitcher? I've seen long-billed dozens of times in California and short-billed often enough, and generally separated them by habitat. By default the long-billed occupied the Bay Area while shorties were more coastal. I guess I even got quite lazy about that because it’s nowhere near a hard-and-fast rule.

Certainly the length of the bill is little use in identifying them, so I’m continually amazed when British birders confidently announce one or the other. I used to have the greatest difficulty with them. So, here's the British trick: if you’ve got a dowitcher, which is rare, it’s long-billed. Short-billed is a mega; the last certain sighting was back in 2005.

Still not sure whether I was looking at the right bird, I decided to play a game of sketching what I did see. Here in words is what I came up with: surprisingly similar size and build as the snipe; grey head and breast with darker cap and possible eyebrow; a slight gap between the breast and coverts/scapulars – rather like a common sandpiper; black-spotted grey coverts under black-spotted rufous scapulars, then back to black-spotted grey on the mantle; and a kind of weird, splayed tail-feather configuration. Google Books shows typical shorebird topography for these terms if you scroll down a little. I had to use it.

The spotting on the feathers signifies a juvenile at this time of year, as do the rufous fringes, so I got those bits right. I’m not too sure what was going on with the tail though! The rest of the description is pretty much spot-on for any dowitcher.

Sketching, in my case just ovals and lines (you should see the tiny head on my effort!), is something I should do more. Again, I tend to get lazy. But not this time, not for my 278th British (sic) bird. Surprisingly it did nothing for the year list: good old Shoreline at Mountain View, CA gave me one back in March. Or was it short-billed? Ha! I don't know. However, this afternoon did push the year list on to 575, thanks to my first water rail – so late in the year. I could reckon on getting to 600 since I have yet to see many of our common winter birds.

Did I mention that I was away last winter? I expect so.

Osprey at Chew Valley Lake

Here's something from ten years ago – August 24, to be exact – when ospreys were still a bit of a novelty:

"I had got up early to catch high tide at Severn Beach. I walked out of the door at seven to the start of some persistent rain and changed my mind instantly. There were hides at Chew Valley and I would at least stay dry. There is nothing to be gained from peering through droplet-coated binoculars while getting soaked and probably blown about into the bargain.

"A good decision. Within moments of settling in to the Stratford Bay hide I saw a large shape above. Great Black-backed Gull was my first thought. I had never seen one at Chew, so that wasn't too bad. An instant later better was to come. The bird turned to reveal splayed wing tips -- way too splayed for any gull. I knew that I could only be looking at an Osprey.

"I watched it hunt and thought how expensive an operation it was. No gliding or soaring in this weather. More or less continuous wing-beats and turns punctuated the odd plummet as the bird saw something only to pull out as its prey disappeared. Once it continued its dive, thrashed around and came out with... Well, was there something? The binoculars did not resolve anything and the Osprey continued its quartering.

"A second dive, thrash and lift-off definitely produced a wriggling victim. I was in a state of tension. Would the bird hold on? This fish definitely did not want to be caught. I could see the Osprey try to straighten its catch as I knew it must before it could fly efficiently. I looked out for gulls that might try to harass the Osprey. Eventually it had its cargo stowed to its satisfaction and powered off overhead and away behind the hide.

"You can see all this stuff on the TV but you will always miss the emotional involvement provided by being there and witnessing the whole chase. I felt nearly as exhausted as the Osprey must occasionally have felt after a hard day's work."