# Fallsview Follies

Discussion in 'Blackjack Tournament Strategy' started by gronbog, Mar 23, 2017.

1. ### hopinglarryTop Member

Appears to be a couple of options for BR1. He can protect against Tim BJ by betting less than 50, but this still leaves him open to both Tim and BR3 winning DDs. He does, however get to bet after BR3 and can DD if he thinks he needs to based on Tim's hand.

I think a better bet might be in the 202.5-247.5 range. If he wins the hand then both BR2 and BR3 would have to get 3 bets on the table to go around him. That would be and extremely low probability for both people to get splits and win all of them. Even if BR1 loses the hand, BR2 and BR3 would both have to have either a BJ or DD win.

2. ### hopinglarryTop Member

Looking at what I said above I think I meant 202.50-297.50. I am not sure that it makes a lot of difference inside that range.

It did make me think about what the odds were for some one to get a hand that could be split. Assuming that I am calculating correctly for a six deck shoe:

For 2-9 it is 23/311 divided by 13 or .005689 and there are 8 of these for a total of .04551 (4.551%).
For 10-K it is 95/311 time 4 divided by 13 = .09398 (9.398%)
Aces are special because I have only played in one tournament over the years where you could DD Aces after a split, so Aces are like a DD and add .005689 to the total adding these up I get .145189 (14.5189%) as the chance to get a split.
For 2 people to get a split hand, we would multiply the split probability and get approximately 2%.

3. ### hopinglarryTop Member

It might be interesting to know what the probability might be for a person to win a blind Double (for lack of a better term) where the cards have not been dealt yet. If someone knows that % I would like it. Gronbog, if you get your simulator working again you could likely calculate this.

4. ### gronbogTop Member

It's generally in the low 30% range, depending on rules. I have a strategy for this. The main point of the strategy is to know whether it's better to split or double your pairs, since, obviously, all other hands must be doubled. The success rate also depends on going on to play the optimal strategy for each split hand (too many sub-tables to post or to ever memorize). Perhaps we need another simplification from S. Yama similar to the one he did for my "Must Win One Bet" strategy. In real-life play, I tend to use a no-bust strategy after splitting when I need to win 2 bets (i.e keep the money in play), since busting one hand would require a resplit of the second hand in order to achieve the goal.

Here is the "Must Win at Least 2 Bets" strategy:

http://gronbog.org/results/blackjac...one/generated/complete/2.0/p1.X/strategy.html

It looks like it was generated a long time ago before I had the capability to estimate the success rate without a separate simulations. I'll regenerate it with that information included.

Here is the thread on "Must Win One Bet"

Gronbog, are saying that BR1 did stand -or- or should have. He should have, but he doubled and made a hand. Pretty much every move he made was wrong, completely lucky win for him. I remembered shaking my head, but thrilled that he gave me an extra chance by the move.

6. ### gronbogTop Member

I thought that he did stand after thinking about it for way too long. Perhaps I am mistaken.

Last edited: Apr 1, 2017
7. ### hopinglarryTop Member

Gronbog, thanks for the information. I am not sure the win rate for blind DDs has much practical value. I consider it interesting because my experience has demonstrated that people like to talk more about how unlucky they were versus how lucky they were. With some probabilities, in the postmortem, one can lament on how unlucky they were

8. ### gronbogTop Member

I use the 30% estimate extensively when weighing the pros and cons of increasing my bet to cover an opponent's 2 bet win. For example it's worth exposing yourself to your opponent's push (approximately 8%) in order to cover his double but not worth it to expose yourself to his single bet win (approximaltely 43%).

Note that 30% figure increases when blackjack pays 2 to 1. I should run that scenario since it is common.

Last edited: Apr 1, 2017

I gotcha, BR 1 wasn't really a factor in this discussion. Thd point of your conversation was excellent and on point. The point of that potential free double by me (- your position as BR4) for a lock, was excellent. Another intriguing conversation.

Agreed, you are correct. However, with Gronbog as my witness, BR1 was extremely lucky. I'm sure GB shares my sentiment that I would welcome BR1 at any of my tables in the future, vs any actual skilled player.

gronbog likes this.
11. ### hopinglarryTop Member

OK, let's look at BR1's bet using Gronbog's 30% blind DD win rate:

If BR1 bets 2.50-47.5 then both players have to win DDs to go around him (i would pick 47.5). This is a 9% shot means he will advance 91% of time. But he could get a BJ which would force BR3 to get 3 bets on the table. Also he plays after BR3 and could if he thought it was necessary DD his own hand taking in consideration BR3 results on the DD and BR2 hand. There would be no defense if BR3 got a split hand and 3 bets of the table. So I believe his advancement rate would still be North of 91%.

If BR1 bets 52.5-197.5 (I would go with 197.5) then BR2 could go around with BJ (assuming BR1 loses) or DD and BR3 would still need at least a DD. If BR1 wins then BR3 would still need 3 bets and BR2 would need a DD. If BR1 gets a BJ then both players would have to win 3 bets which is a very low probability (less than 2%). I don't know what all these probability come to. But his advancement rate is going to be very high.

If BR1 bets 202.5-297.5. If he loses the hand then both BR2 and BR3 would need BJ or DD to pass him. If he wins the hand (he has a virtual lock higher than 99%), since then both would need to win 3 bets (only a 2% chance of both getting 3 bets on the table and less than that because they both have to win all of them). I don't know what all this comes too, but I still think I would go with 297.5 as my bet of choice for the 3 ranges.

12. ### gronbogTop Member

I found some time to look into this and found the problem. Thankfully it was an infrastructure problem and not a bug in the strategy generation algorithm.

I will now try to find the time to run sims of some of the alternatives that have been discussed here.

13. ### gronbogTop Member

Here's a result which confirms our initial assessment of the simplified situation. This was the situation where we considered only Tim's position vs that of BR3.

BR3: bankroll 1850: Bet 500, doubles for 500 ending up with 16
Tim: bankroll: 2000: Bet 500, hard 19
Dealer: 4

The generated strategy is: http://gronbog.org/results/blackjack/strategy/tournament/FallsviewFollies/simplified.html

This chart confirms a few things that we talked about.
1. Tim should double or split any initial hand he has in this situation (free double), including blackjack (if allowed). The rows for 20, 21 and A,10 recommend standing because they can only occur for hands with more than 2 cards

2. If Tim can double or split and not bust, he has a 100% chance of advancing. To see this hover your mouse over any cell for which
• the total is less than 12
• the hand is soft
• the hand is a pair
3. If Tim chooses not to double or split, it doesn't matter whether he hits or stands. His success rate becomes that of the dealer not busting. This is because BR3 has 16 and thus cannot push and only advances if the dealer busts.

14. ### gronbogTop Member

Adding me into the mix complicates the situation, as expected:

http://gronbog.org/results/blackjack/strategy/tournament/FallsviewFollies/withGronbog.html

The risk of busting makes it too dangerous to double most high hard hands and the risk of ending up with a low total makes it too dangerous to double several hard low hands. When not doubling these hands, it still doesn't matter whether Tim hits or stands, however the software never recommends standing on hard totals less than 12 and it favours standing over hitting otherwise.

Tim's actual hand of 19 is a stand, as expected.

15. ### gronbogTop Member

This estimate appears to be accurate. For the simplified situation the sim shows: Double: ~66.6%, Hit/Stand: ~60.2%
The sim when adding me to the mix shows: Hit/Stand: ~60.1%, Double: ~51%. This shows a 15.6% degradation for doubling vs S. Yama's 8.5% estimate. On the other hand, doubling is now about 9% worse than hitting/standing. Is this how S. Yama's estimates should be interpreted?

16. ### gronbogTop Member

The sim recommends standing on 18 and 17 and doubling on 16 or less.

17. ### gronbogTop Member

S. Yama contacted me privately and correctly deduced that my sim configuration had Tim doubling for the full amount. This makes it possible for me to beat him when he busts by simply winning my hand. All of the discussion above assumed that Tim would force me to win a double by doubling for between 352.50 and 410. A sim for the proper situation is underway.

18. ### gronbogTop Member

I reconfigured my simulator to create a situation which is the same as adding me to the mix. I say "which is the same as" because my tournament strategy generator does not support the discovery of doubling for less for arbitrary amounts. Instead, what I did was to alter Tim's bet so that he can double for the full amount and still force me to win a double. The amount is also large enough so as not to jeopardize his high position. Here is the adjusted situation:

BR3: bankroll 1850: Bet 500, doubles for 500 ending up with 16
Tim: bankroll: 2000: Bet 455, hard 19 <-------- Tim's altered bet
Gronbog: bankroll: 587.50: Bet 500, soft 16
Dealer: 4

I have updated the link to the resulting strategy table for Tim:
http://gronbog.org/results/blackjack/strategy/tournament/FallsviewFollies/withGronbog.html

and here is the link to the strategy for the original simplified situation (without me in the mix)
http://gronbog.org/results/blackjack/strategy/tournament/FallsviewFollies/simplified.html

This estimate is still confirmed. The cell for 19 vs 4 in the strategy for the simplified situation contains: Double: 66.6%, Hit/Stand: 60.2%

This estimate is now also confirmed. The cell for 19 vs 4 in the strategy with me in the mix contains: Hit/Stand: 60.2%, Double 58.4%. The penalty for doubling with me in the mix is 66.6% - 58.4% = 8.2%, which is very close to S. Yama's estimate. The decision is therefore to Stand.

19. ### gronbogTop Member

Confirmed:
The cell for 18 vs 4 in the strategy for the simplified situation contains: Double 69.6%, Hit/Stand: 60.2%

The cell for 18 vs 4 in the strategy for mein the mix contains: Double: 62.2%, Hit/Stand: 60.2%. The penalty for doubling is 69.6% - 60.2% = 7.4%. The decision is to double.

20. ### London ColinTop Member

62.2 - 60.2 = 2% for the case with you in.

Your sim numbers are fairly close to the ones I calculated -

Last edited: Apr 25, 2017