Steve, I greatly appreciate you pointing out that EV is just one of many
possible values on which to base a strategy. Let's take a for-instance: in
a quickest-royal strategy, an extreme case but possibly useful in certain
tournament situations, I presume you would hold only high cards of the same
suit, 2-card royal > 1 high card, etc. You would throw away anything else.
This would be an extremely simple strategy for which to compute the return.
Yes, this gives the highest probability of hitting a royal on the very next
play, which is the same as minimizing the average number of plays needed
to hit a royal. For 9/6 JoB, the EV for this strategy is 55.016%, so it is
extremely costly to always try so hard to hit a royal, but this strategy
reduces the royal cycle from 40390.5 to 23164.7, so royals do occur much
more often when this strategy is used.
On average, a player will lose 11220.37 units between royals, by playing
so aggressively. In contrast, the min-cost(royal) strategy reduces the cost
to 976 units per royal.
The bankroll needed to give a 50/50 shot at the royal, when using this
strategy, is 7778 units, as opposed to the 720 unit bankroll needed for
the best-shot(royal) strategy.
But in a min-royal strategy, which I assume you mean hitting a royal in
the fewest # hands while preserving bankroll, how do you know where to draw
the line? For example, in 9/6 JOB, would you keep all 3-card royals over
high pairs, or just 4-card flushes, or what? In other words, how do you
juxtapose the two criteria, hitting a royal versus preserving bankroll? I'm
guessing that it's where the two individual criteria would intersect on a
graph. And how would the resulting strategy differ from max-EV strategy, if
at all?
I don't recall using the phrase "min-royal strategy" so I'll assume you meant
to say "best-shot(royal) strategy." The idea behind best-shot(royal) isn't to
hit the royal quickly (the max-royal strategy you describe above is best at
that), and it isn't really designed to preserve bankroll (the min-cost(royal)
strategy is best at that). It also doesn't try to balance opposing goals,
but tries to do just one thing: maximize the probability of _eventually_
hitting the royal. This is sort of the opposite of trying to hit a royal as
soon as possible, and the solution it tied directly to my RoRBR formula,
which is used to compute the overall probability of eventually hitting the
royal.
I've developed a method called "virtual payoffs" that I use to compute
optimal strategies. The math behind it is a bit complicated, but the idea
is really quite simple. What I do is pretend that we're playing a game that
is slightly different than the actual game. This is done by pretending that
the payoffs are different than their actual values, so that "virtual" values
are used in place of each real payoff. Then, I use a VP program to find
the best strategy for a game that uses these virtual payoffs, by maximizing
"virtual EV" instead of maximizing "actual EV." The big trick here is to
find a formula that turns real payoffs into virtual values that correctly
represent the desired objective.
It would require a lot of highly technical posts to give a detailed
description of how this works, so I won't try to do that right now, but I can
give several examples of virtual payoff tables that I've used to find some
optimal strategies. For these examples, I'll use a 9/6 JoB game with a
royal jackpot of 1300 units. This gives the game a healthy EV for the
player so that RoR can be used for one of the examples.
The following table shows virtual payoffs that apply to the 9/6 JoB game.
For the Max-EV strategy, the actual payoffs for the game are used. I've
rounded the virtual payoffs for this table, but when I compute optimal
strategies the virtual payoffs are specified to 14 digit accuracy. These
numbers are all very precisely defined.
<pre>
Max Min Min Max
Hand EV RoR bs_RF mc_RF Cost Royal
···
On Friday 25 November 2005 01:07 pm, John wrote:
-------------------------------------------------------------------------------------
Royal 1300 1003.5 1038.7 975.99 1277.9 1
Str-flush 50 49.492 48.839 50 49.166 0
4/kind 25 24.875 24.713 25 24.591 0
Full House 9 8.9850 8.9654 9 8.8638 0
Flush 6 5.9937 5.9856 6 5.9149 0
Straight 4 3.9975 3.9942 4 3.9489 0
3/kind 3 2.9987 2.9971 3 2.9660 0
Two Pair 2 1.9996 1.9990 2 1.9830 0
High Pair 1 1 1 1 1 0
-------------------------------------------------------------------------------------
</pre>
The optimal strategy for each of these cases is found by plugging the
virtual payoffs into any VP program that computes a max-EV strategy.
I don't know if any commercial VP programs will allow non-integer
payoffs to be entered, but my own program supports this, and it is
very useful for studying alternate strategies. If the commercial programs
don't allow this, you might try multiplying all payoffs by 100 or 1000
and rounding to approximate the virtual payoffs.
For 9/6 JoB there is a simpler trick for finding the best-shot(royal)
strategy. Changing the royal payoff to 1038, while leaving all other
payoffs at the actual values, just happens to give the correct RoRBR
strategy. The same strategy results from any royal payoff between
1022 and 1043. However, this kind of trick doesn't work for 8/5 JoB
or for 10/7 DB, and I haven't tried it for other games.
Here a quick summary of what each of these strategies is trying to do:
Min-RoR minimizes overall risk-of-ruin, which is equivalent to maximizing
the probability that the player will play forever without ever going broke.
The 50/50 bankroll for this strategy is 1661 units, which gives the player
a 50% chance of playing forever without going broke. The max-EV strategy
gives a 50/50 bankroll of 1670 units.
The bs_RF column is best-shot(royal) strategy, which maximizes the
probability of hitting a royal before going broke. This strategy has a
50/50 bankroll of 720 units, which gives the player a 50% chance of
hitting a royal before going broke. This bankroll is smaller than the
50/50 bankroll for Min-RoR strategy, because the task of hitting a royal
is easier than the task of playing forever. The max-EV strategy gives
a 50/50 bankroll 731 units when trying to hit a royal before going broke.
The mc_RF column is min-cost(royal) strategy, which minimizes the
average loss that occurs between royal flushes. When the royal payoff
if 975.99 units, royals occur just often enough to pay their own cost,
making the game exactly breakeven. By comparison, the average loss
between royals when playing the Max-EV strategy is 984.299 units.
The Min-cost column is the strategy that maximizes the average number
of units returned per unit consumed by losses. This views the game as
if you were playing at a casino on the border between two countries and
using the VP game to exchange currency. If the VP machine accepted
only U.S. dollars but made all payoffs in Canadian dollars, then this strategy
would give the player the best possible exchange rate. For this game,
each dollar paid back to the player costs only 98.297651 dollars that are
paid to the machine in lost wagers, on average. This strategy can also
be viewed as a "best winning streak" strategy. If you start with one unit
and collect your net winnings, but re-play only the original unit and keep
playing until you eventually lose, then this strategy maximizes your average
payoff from these winning streaks. By comparison, the Max-EV strategy
has an average cost of 98.297656 units lost per unit returned to the player.
This strategy is almost identical to Max-EV for this game, and this tends
to hold true for most games.
The Max-Royal strategy tries to hit royals at all costs. This strategy would
discard a dealt straight-flush in order to try for a royal instead. This
would be the right play to make on the last few hands of a tournament,
if your only hope for winning a prize is to hit a royal flush. Otherwise,
this strategy is a great way to burn through a bankroll in a hurry.
The strategy shown below is best-shot(royal) strategy. It tries for royals
a little more often than max-EV strategy.
Jacks or Better 9/6 best-shot(royal)
Distribution of Final Hands
----------------------------------------------------------------
Final Hand Payoff % Hit Cycle % Return
----------------------------------------------------------------
Royal Flush 5190 0.0028460595763 35136.29891406983 2.95420984020
Straight Flush 250 0.0111604568767 8960.20665686290 0.55802284383
4/Kind 125 0.2353418470304 424.91380628578 5.88354617576
Full House 45 1.1479534453312 87.11154655854 10.33158100798
Flush 30 1.1150247530435 89.68410766402 6.69014851826
Straight 20 1.1268006944393 88.74683916463 4.50720277776
3/Kind 15 7.4107982065493 13.49382309609 22.23239461965
Two Pair 10 12.8859149191077 7.76041131947 25.77182983822
High Pair 5 21.2456549993828 4.70684476440 21.24565499938
----------------------------------------------------------------
45.1814953813371 2.21329549091 100.17459062103
Recommended Strategy
High cards: AKQJ
------------------------------------------------------------
Rank Return Cards to keep
------------------------------------------------------------
1 1038.0000 Royal Flush
2 50.0000 Straight Flush
3 25.0000 4/Kind
4 23.7680 4/royal
5 9.0000 Full House
6 6.0000 Flush
7 4.3025 trips
8 4.0000 Straight
9 3.5551 4/str-flush (0 holes)
10 2.5957 two pair
11 2.3825 4/str-flush (1 hole)
12 1.7155 suited KQJ
13 1.7119 suited QJT
14 1.6221 suited AQJ/AKJ/AKQ
15 1.6185 suited KJT/KQT
16 1.5365 pair (AKQJ)
17 1.5334 suited AJT/AQT/AKT
18 1.2170 4/flush
19 0.8723 unsuited KQJT
20 0.8237 pair (T98765432)
21 0.8085 unsuited QJT9
22 0.7447 unsuited JT98
23 0.7313 3/str-flush (1 hole, 2 high)
24 0.7266 3/str-flush (0 holes, 1 high)
25 0.6809 4/straight (0 holes, 0 high)
26 0.6366 3/str-flush (2 holes, 2 high)
27 0.6312 3/str-flush (1 hole, 1 high)
28 0.6255 3/str-flush (0 holes, 0 high)
29 0.6224 suited QJ
30 0.6064 suited KJ/KQ
31 0.5957 unsuited AKQJ
32 0.5902 suited AJ/AQ/AK
33 0.5362 3/str-flush (2 holes, 1 high)
34 0.5319 4/straight (1 hole, 3 high)
35 0.5304 3/str-flush (1 hole, 0 high)
36 0.5153 unsuited KQJ
37 0.5117 suited JT
38 0.5024 unsuited QJ
39 0.4976 suited QT
40 0.4893 unsuited KJ/KQ
41 0.4838 suited KT
42 0.4813 Jack
43 0.4774 Queen
44 0.4771 unsuited AJ/AQ/AK
45 0.4752 suited AT
46 0.4731 King
47 0.4715 Ace
48 0.4349 3/str-flush (2 holes, 0 high)
49 0.3603 (draw 5 cards)
------------------------------------------------------------