Doubling down on 12: Insanity?

I've been playing blackjack off and on for 30 years. and it thought I had seen some pretty weird plays. But a few nights ago a player at my table had me shaking my head again and again.

From his small-talk and mannerisms, he obviously was not an amateur. He bought in for $200 ($15 min table) and 45 minutes later he cashed out for $775. (It was a fairly hot table, I took profits of $350 after about 90 minutes session.)

This was a 6-deck, 5/6 penetration, DDAS, resplit Aces, dealer hit S17 game.

He made many unconventional plays, but the one that boggled mind the most was him doubling down with a hand of 12, vs dealer 5 or 6.

He did this 4 or 5 times, and hit all of them. Not only did he not draw a 10-card, but the dealer did bust each time. I don't recall the exact True counts at the time he made these plays, but they were mostly positive because I recall I had larger than my minimum bet in place a couple of times.

I'm pretty sure he was counting on some level because his big bets were more or less in line with mine, using basic Hi-Low).

Any comments?

From his small-talk and mannerisms, he obviously was not an amateur. He bought in for $200 ($15 min table) and 45 minutes later he cashed out for $775.

Small-talk made by skilled players, if they talk at all, is usually to try to make themselves look stupid and fit in as a typical casino patron, not to seem smart.

He made many unconventional plays, but the one that boggled mind the most was him doubling down with a hand of 12, vs dealer 5 or 6.

It is likely he is a degenerate gambler who thinks he knows how to play well. The situations where this double down would be correct are few and far between. Anyone who knows such plays would probably not be playing for tiny stakes ($200 buy in).

(It was a fairly hot table, I took profits of $350 after about 90 minutes session.)

What is a "hot table?"

To me a "hot" table is one where the count was solidly positive much more often than it was negative. Is there a better definition?

I'm definitely still a newb at "serious" blackjack, but this was my best 90 minute or so session.

If Mr. DD12 was a pro, he was playing the role of a typical tourist, making small jokes, rooting for the right card to come up.

This is why smart sharp casinos run multiple skills checks on players before making a decision. They guy you were watching could have been influenced as to his bet sizes by your bets or any number of other factors not related to the count.

You decided the guy was counting and that if he was successful in doubles on hard 12 he must have some other knowledge. He was very lucky and that is about it. If he had taken the time to learn to count cards (or even watch for high and low cards) he would not have doubled on a hard 12 unless he caught a next card flash and it was an 8 or 9.

To me a "hot" table is one where the count was solidly positive much more often than it was negative. Is there a better definition?

I think 4-Card Charlie's definition is fine since he used a past tense verb, and especially since he did it twice. Nothing wrong with looking back on a table that was hot or a streak of winning hands after they have happened.

The fallacy is thinking that one can predict them.

I developed a system where the A count is + 1 for 2-5, the B count is +1 for 6-9 and a ten valued card subtracts 1 from both the A and B counts. I have an index value to double down on 12 vs dealer 6 up.
It is B<=-6 to double down. I have never done this because I figure it would bring unwanted attention and the dealer would call this play to the pit's attention.

It is thus reasonable to double on 12 vs. 6 when there are a lot of
6-9 valued cards left.

This could be a very expert player doing that.

I have not simulated rodomonte's AB count, but it seems to me that using this count in addition to a primary count such as High-Low, Hi-Opt or KO adds an amazing level of complexity to the game and the favorable situation occurs extremely rarely. Doubling with 12 has a 4/13 or > 30% probability of busting off the top of the deck. This is too high to make this play advisable in all but the most negative counts. Even in a very negative count, you are unlikely to get 20 or 21 unless there are disproportionate numbers of 8s or 9s remaining. also, the dealer is less likely to bust with a very negative count. The player is likely to get a total 14, 15 or 16, while the dealer gets a multi-card hand of 17, 18, 19 20 or 21. Therefore, without running a simulation, I think that a side count of 8s and 9s, combined with a regular count, would be a better indicator of whether to double with 12 v. 6 than rodomonte's AB count.

Rodomonte, do you have any simulation data? As a practical matter, I would advise against doubling with hard 12 (or higher).

The play 12 v 6 has an expectation of -17% if you hit. But in order to make doubling worthwhile the ev would have to turn into positive and no count in the world can achieve that with a reasonnable frequency.
Conclusion: If you see somebody doubling on 12 there is a 100%-chance he has no clue about Blackjack.

Francis Salmon

>>Conclusion: If you see somebody doubling on 12 there is a 100%-chance he has no clue about Blackjack.

Normally doubling 12 is a very bad play, however there are occasions, such as when the player is being evaluated as a possible AP or if comps are generated based on the casinos edge over the player, that occasionally doubling 12 especially with a minimum bet in minus counts could be a smart play similar to making a very small Insurance bet in a neutral or minus count.

But the whole thread was about somebody who did this play regularly even in high counts and with big bets and some people were wondering whether this man was a particularly gifted card counter since he was successful with these plays.
I just say that this is totally absurd.

Francis Salmon

rodomonte,

I ran a CVIndex sim using your "B" count to generate the H/S indexes for 12 vs. 4, 5, and 6. Below (WAY below... damn HTML formatting!) you'll find the three tables that show the H/S indexes for these three plays.

For 12 vs. 6, at a TC (I assumed your B count is true-counted) of -2, the Hit EV is -0.148102, and a plot of Hit EV vs. TC appears to have a slope of -0.012 (each time the TC falls by 1, the Hit EV rises (becomes less negative) by roughly 0.012). If we extrapolate this trend, we can see that, when the TC falls to roughly -14.34, the EV for Hitting will be about zero.

Now we know that, for DD to be preferred to Hit, the Hit EV must be positive (otherwise, why put out more money, when we can simply hit for free?). When the Hit EV is positive, the DD EV is, at most, 2*(Hit EV). For cases where, if we were to hit, we would NEVER take a second card, DD EV = 2*(Hit EV); for other cases, DD EV < 2*(Hit EV). For example, using B.S., if we have 11 vs. 6, we know that we'll take only one more card, since even if we get an Ace we won't hit 12 vs. 6. In this case, the DD EV is precisely twice the hit EV. On the other hand, with 11 vs. 9, if we were to hit and receive an Ace, B.S. would say to hit again. That's why, for 11 vs. 9, the DD EV is less than twice the hit EV.

This means that, for TC's above roughly -14.34, DD cannot be the correct play.

Hope this helps... and saves you a boatload of $$$!

Dog Hand

P.S. You can remit my "cut" through Stanford Wong ;-)

(It was a fairly hot table, I took profits of $350 after about 90 minutes session.)

I hope you mean you left because you were spending too much time there and not because you wanted to quit while your ahead. Such a strategy is voodoo and does not belong in an AP's arsenal.

Thanks Rick,

Yes, unfortunate choice of words on my part. To put it correctly, my profits were $350 when I completed my session.

If you catch a 9 a few times it might bring instant backoff. I used to double down hard 16 vs 7 for less ($1 toke for dealer). After two consecutive times catching a 5 the pit got very pissed off and declared that I had to bet at least the table minimum on my double down bet or I couldn't do it. (Grand Tunica $25 single deck game in HL room).

and you catch the perfect or near perfect card the size of your bet usually becomes irrelevant to the suit you're trying to fool.

to me a "hot" table is one where the count was solidly positive much more often than it was negative. Is there a better definition?

Yeah, there is no such thing.

I'm definitely still a newb at "serious" blackjack, but this was my best 90 minute or so session.

Congratulations and many more!

If Mr. DD12 was a pro, he was playing the role of a typical tourist, making small jokes, rooting for the right card to come up.

Making unusual plays could be a sign of a "Pro", but not when he's doubling a hard 12 every time it comes up. (On the other hand, if he has the right information, he could double then, too!) And as Bear says, talking at the table is generally not a sign of serious players.

Probably just got lucky. In the short term anything can happen.

Regards,
PM

and 1.5 decks left to play in a 6d game...

That was you?.... That must have been me!

Those were the only hands I was winning. Couldn't win with a 20,21, or BJ for that matter.

12 vs 5, the TC was like a -4,
Everyone else DD and made their hands so hey.. if everyone else was going to DD and make their hand.. why shouldn't I?.. you need a bit of cover every once in a while at a min bet, and I rarely ever use one...

Pulled a 18 and dealer busted... saved the table...hehe

but DD 12 every time, no way it definately was Not I.

But I do hit 12 vs 5's and 6's if the index calls for it. Really stirs up the others players at the table.

BJC

Even if he had information, he wouldn't be doubling on hard 12...that would draw too much attention. Yes, he would make some weird plays, but not that.

Regards,
PM

A hot table can be one where several hot looking women are sitting.

A hot table can be one where the RFID wiring under the table starts burning up.

A hot table can be one where the heat vent is blowing directly upon the players at that table.

A hot table could be stolden.

A hot table could be many things but I think all of them have nothing to do with your winning or losing.

BJCount,

Why play shoes at such negative counts? DD ,I can understand but heck, even they demand a wongout once in a while.

regards
waugh