Thursday, September 20, 2012

What Card Should I Lead? Lightning Round Edition


One of the great things about our huge database of cribbage games is that we can identify hands that are frequently misplayed. Today we're going to give a high level overview of a few of those hands. Keep in mind that these results aren't our opinions -- they're the actual results across a sample of millions of cribbage hands. Some of these results are just as surprising to us as they are to you.

A-4-X-X

About 4.8% of pone (non-dealer) hands will hold an ace, a 4, and two 10s/face cards. (From now on we'll use "X" as a shorthand for "a 10 or a face card"). Most players lead the 4 from this hand, but around 7% lead the ace. The players that lead the ace, on average, have a 0.55 point pegging advantage: they peg 0.18 points more, and their opponents peg 0.37 points fewer.

Why is the ace a better lead? There are pros and cons to either lead, but our data shows that by far the biggest factor is that dealers are less likely to pair an initial ace. Of the tens of thousands of A-4-X-X hands that we've analyzed we've seen that the dealer pairs a lead 4 at 19.93% of the time, but only pairs a lead ace 12.84% of the time. An interesting and common case is when both players have A-4-X-X hands. Here's how the pegging plays out in that scenario when dealer is willing to pair a 4 but not an ace:

Pone leads a 4


Pone
Dealer
Points
4
4
+2 for dealer (pair for 2)
X
X
A
A
+3 for dealer (pair for 2 and a go)
X
X
+1 for dealer (go)


Pone leads an Ace


Pone
Dealer
Points
A
X
4
+2 for pone (15 for 2)
4
+2 for dealer (pair for 2)
X
A
+1 for dealer (go)
X
X
+1 for dealer (go)

Leading the 4 gives dealer 6 points to pone's 0 for a net disadvantage of 6. Leading the ace gives dealer 5 points to pone's 1 for a net disadvantage of 4. Executive summary: lead the ace from A-4-X-X.

A-7-8-9

Most players lead the 8, but leading the ace gives a 0.78 point advantage (pone pegs 0.38 points more, and dealer pegs 0.40 points fewer). The data shows dealers making a couple mistakes when pone leads the ace:

  • Dealers holding 5-X-X-X see the ace and expect pone to have a 4. Dealer plays her 5 to avoid giving pone a a 15-2. Pone plays a 9 on dealer's 5 and pegs 15 for 2 points.
  • Dealers holding middle cards (6s through 9s) end up trading runs back and forth with pone, and usually lose in this situation

Executive summary: lead the ace.

A-A-5-9, and A-6-8-9

At the risk of seeming predictable, we're going to suggest leading the ace for these two hands. A-A-5-9 is one of the few hands that most players are playing properly: 50.3% of Cribbage Pro players lead the ace from this hand.

Leading the ace from A-A-5-9 averages a 0.50 point advantage over leading the 9. Leading the ace from A-6-8-9 averages a 0.57 point advantage over the 8 (the most popular lead, and the second best choice).

Executive summary: lead the ace.

5-5-6-7

The last hand we'll look at today is 5-5-6-7. Most players correctly lead the 7, but about a third lead the 6. Leading the 7 gives a 0.57 point advantage over the 6.

The big story here is that pone comes out better if dealer plays an 8 on pone's 7 than if dealer plays a 9 on pone's 6. When dealer plays an 8 on pone's 7, dealer averages 7.59 points of pegging to pone's 3.68 (for a net -3.91 loss for pone). When dealer plays a 9 on pone's six, dealer averages 5.99 pegs to pone's 0.88 (net -5.11 point loss for pone).

That's it for today

Disagree with these results? Want to see the results for another hand? Leave us a comment below and we'll get back to you.

Editor's Note: This is a guest post by Aaron Harsh continuing the series on cribbage strategy and tips. Aaron lives in Portland, Oregon with his wife Stacy and daughter Audrey. He spends his evenings analyzing cribbage strategy for Fuller Systems, and his days analyzing television viewership for Rentrak Corporation's Advanced Media & Information group. You can play him on Cribbage Pro Online as user "aaronhars", or in person at American Cribbage Congress grassroots club #28 (Oregon's Finest).

Friday, September 7, 2012

What card should I lead? (Part 2)


Today's topic is on playing 4-5-6-6 as pone. This is going to be short and sweet, because the wrong way to play this is just so wrong! This is one of the first hands cribbage players study when they begin to take the game seriously, and playing it correctly is a great way to start improving your game.

Lead the 6 and trap the dealer's 5

It would be foolhardy to lead the 5, and the data shows that Cribbage Pro players rarely do that. But 32% of players are leading the 4 from this hand, and that's just plain wrong. Here's why (keeping in mind that the two most common hands for dealer to have are 5-10-J-Q and 5-J-Q-K):


PoneDealerPoints
6
K
6
5
4+5 for pone (run for 3 and 31 for 2)
Q
5+2 for pone (15 for 2)
J+1 for dealer (go)


This play is commonly referred to as the "non-dealer 5 trap." The dealer is trapped after pone plays her second 6: the count is 22, and the 5 is the only card she can play without taking the count over 31. Pone ends up pegging 7 points to dealer's 1, leaving pone with a net 6 point advantage.

That's awesome! Let's talk about it some more!

One of the great things about this play is that the dealer has no escape route: he can't play his 5 on pone's initial 6 (he'd be out-pegged 9 to 1 if he did), so he has no hope but to sit back and watch pone peg away. Personally, my heart sinks a little when I've got 5-J-Q-K and pone leads a six.

Another great thing about this play is that it works fairly often. Pone scores her 7 points as long as dealer's hand is made up entirely of 10/face cards and 5s. Dealer has one of those hands about 9% of the time, which is pretty often in cribbage terms.

You can peg almost as many points without the 5. Any hand with a 4 and two 6s in it is a candidate for this five trap. You won't score that last 15 for 2, but you'll still get the run for 3 and the 31 for 2.

In a defensive situation? Lead the 6

Surprisingly the 6 is a better defensive lead than the 4. On average the dealer pegs 3.90 when pone leads the 6, vs. 4.05 when pone leads the 4. (These averages are based on several thousand 4-5-6-6 hands played on Cribbage Pro Online).

Even better, when pone leads the 6 dealer is limited to just one point 22% of the time, vs. 9% of the time when pone leads a 4. Here's a chart that shows the dealer pegging probabilities for the two leads:


There's a 22% chance that the 6 lead will hold the dealer to 1 point of pegging, but only a 9% chance that the 4 lead will do that. The 4 lead's only advantage is that it's slightly more likely to keep dealer's pegging under 8 points (8.82% chance of dealer pegging 8+ points if you lead the 4, vs. a 9.15% chance if you lead the 6).

Executive summary: there's no defensive advantage to leading the four.

Desperately need to peg a point? Lead the 6

Here's a similar chart, showing pone pegging probabilities.  Note that we swapped the “=”s out for “=”s in this chart -- the “=1” bar in this chart shows the chances that we’ll score at least one point, rather than at most one point.

The 6 lead wins across the board: you're more likely to peg at least one point when you lead the 6 (67% chance, vs. 56% when you lead the 4), and more likely to score at least two points (52% for the 6 vs. 40% for the 4). In fact, no matter how many points you need to peg, you're more likely to get those points if you lead the 6.

Executive summary: there's no offensive advantage to leading the four.

Moral of the story

The 6 lead is superior in ability to score a small number of points, ability to score a large number of points, and ability to keep dealer from pegging. You should always lead the 6.

Is there ever a situation where the 4 is the right lead? Leave us a comment and let us know what you think.

Editor's Note: This is a guest post by Aaron Harsh continuing the series on cribbage strategy and tips. Aaron lives in Portland, Oregon with his wife Stacy and daughter Audrey. He spends his evenings analyzing cribbage strategy for Fuller Systems, and his days analyzing television viewership for Rentrak Corporation's Advanced Media & Information group. You can play him on Cribbage Pro Online as user "aaronhars", or in person at American Cribbage Congress grassroots club #28 (Oregon's Finest).