# What's wrong with 2 point matches?

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### Loren Finkelstein

Mar 3, 1999, 3:00:00 AM3/3/99
to
Maybe I am showing my inexpertise here, but I have seen people comment
that 2 point matches are "a bad thing" [TM]

Someone in the NIHILIST discussion said that 2 people who know what they
are doing may as well just be playing a 1.

Why?

Isn't doubling an integral part of the game? I often use doubling as a
tool while playing, so I prefer matches that are more than 1 game. Why
would this be less useful in a 2 point match?

Thanks,
Loren

### Julian Haley

Mar 4, 1999, 3:00:00 AM3/4/99
to
Once you understand the strategy of a 2 pointer (its a glorified 1 pointer),
you will find the doubling threshold in a two point match is so low, there
is almost no skill involved when handling the cube

THe advantages of 2 pointers for people wanting to elevate their rating are:

- novice players often make horrendous cube errors in 2 pointers (either
holding the cube for far too long, or incorrect drops)
- the rating points exchanged for a 2 pointer are higher than that of a 1
pointer

julian

Loren Finkelstein wrote in message ...

### Tom Penney

Mar 4, 1999, 3:00:00 AM3/4/99
to
Julian is correct. When both players are 2 points away from wining a
match it is correct to double with anything over 50% chance of wining.
It is correct to take with as little as a 30% chance of wining. Look
at it this way. If you are favored to win the game wouldn't you rather
have the whole match on the line? even if you are only favored a
little?

I do disagree with the statement that there is something wrong with 2
point matches. 2 point matches are fun. Why play a one pointer when
you could play a "glorified" one pointer? If a player doesn't
understand the 2 away - 2 away cube strategy then he deserves the
disadvantage he has by not doubling early. Furthermore his rating
probably reflects his understanding of this concept. Difference in
rank is figured into the points earned.

If you don't like 2 pointers no one says you have to play them. If you
both understand, and want to play a quick game for higher stakes, why
not?

Tom Penney

### internat...@yahoo.com

Mar 4, 1999, 3:00:00 AM3/4/99
to
In article <loren-03039...@r82aap000858.nyr.cable.rcn.com>,

lo...@panix.com (Loren Finkelstein) wrote:
> Maybe I am showing my inexpertise here, but I have seen people comment
> that 2 point matches are "a bad thing" [TM]
>
> Someone in the NIHILIST discussion said that 2 people who know what they
> are doing may as well just be playing a 1.
>
> Why?
>
> Isn't doubling an integral part of the game? I often use doubling as a
> tool while playing, so I prefer matches that are more than 1 game. Why
> would this be less useful in a 2 point match?
>

The current fad in backgammon dictates that at some point in the first game
of a 2-point match, there must be a double. That is, a player must double as
soon as he or she has an advantage, however slight. Since this will normally
occur when the advantage IS slight, it follows that the doubling player's
opponent must accept. Accordingly, virtually every 2-point match should be
decided in 1 game. Some apparently regard this as distortive of the
ratings.

In addition, assuming that the current fad in fact prescribes the optimal
strategy, there are those who believe that knowing this strategy gives a
player an unfair advantage over players who do not. Why this particular bit
of knowledge should be singled out as giving an "unfair" advantage, while it
is not regarded as unfair to be kitwoolsey, is beyond me. But there it is.

-----------== Posted via Deja News, The Discussion Network ==----------

### Walter Trice

Mar 4, 1999, 3:00:00 AM3/4/99
to

Tom Penney wrote in message <36de1b21....@news.goldengate.net>...

>Julian is correct. When both players are 2 points away from wining a
>match it is correct to double with anything over 50% chance of wining...
[snip]

A common misconception. Actually you don't need to be a favorite in the game
to double. Consider the following bearoff position:

- - - - - -|
O|
|
<- off |
|
X X|
- - - - - -|

X's cubeless probabiity of winning is 39.9%, so that is his probability of
winning the match if he doubles.

If he doesn't double, he gets a 70% match winning probability if he rolls
one of the 8 numbers that bear off, and a 30% chance if he rolls one of the
other 28 (because he should drop his opponent's cube, having only a 25% or
less cpw.)

So his total mwp. would be 8/36*70% + 28/36*30% = 38.9%, which is less than
what he would get by doubling.

This situation turns out to be fairly typical. In a race it is usually right
to be doubling with a cpw around 40%. In a LONG race, you may need as much
as 41% or 42% to double.

-- Walter Trice

### Richard McIntosh

Mar 4, 1999, 3:00:00 AM3/4/99
to
On GamesGrid, the ratings change for a 2 point match is the same as for a 1
point match, thereby removing some of the "benefit" of playing 2 point matches.
There is still some advantage for the knowledgeable player when playing someone
who doesn't understand appropriate cube action, in that their better knowledge
affords better match-winning chances, but there is no ratings benefit.

One should not accept an invitation to play 2 points non-Crawford, unless one
fully understands the implications. In the just-released GamesGrid client 2.1,
such an invitation (any which involves non-standard rules of engagement) is
accompanied by a warning message to the effect that non-standard conditions-of-
contest have been offered. One is still free to accept them, of course.

Richard McIntosh
VP Engineering
The GamesGrid
http://www.gamesgrid.com

### Robert-Jan Veldhuizen

Mar 5, 1999, 3:00:00 AM3/5/99
to
On Thu, 04 Mar 1999 05:36:03 GMT, bl...@bigfoot.com (Tom Penney) wrote:

>I do disagree with the statement that there is something wrong with 2
>point matches. 2 point matches are fun. Why play a one pointer when
>you could play a "glorified" one pointer? If a player doesn't
>understand the 2 away - 2 away cube strategy then he deserves the
>disadvantage he has by not doubling early. Furthermore his rating
>probably reflects his understanding of this concept. Difference in
>rank is figured into the points earned.
>
>If you don't like 2 pointers no one says you have to play them. If you
>both understand, and want to play a quick game for higher stakes, why
>not?

Well, just to be picky, if both players know the strategy for a 2pt
match and apply it (almost) perfectly, we're effectively talking about a
2-in-1pt match, which is not "fair" for the same reasons as a 99-in-1 is
not fair. However, the effect is pretty small so I don't see any
practical problems with it :-)
--
Robert-Jan/Zorba

### Sander van Rijnswou

Mar 5, 1999, 3:00:00 AM3/5/99
to
> Well, just to be picky, if both players know the strategy for a 2pt
> match and apply it (almost) perfectly, we're effectively talking about a
> 2-in-1pt match, which is not "fair" for the same reasons as a 99-in-1 is
> not fair.

Just to be picky, in a 2 point match both players have to double
CORRECT to get a 2-in-1. To get a 99-in-1 both players
have to double INCORRECT. So the first is fair and the second
is not.

(Can anybody produce a sequence of dice with wich it is
reasonable to get 8 cubes in a row?? (in a 99 point
match say, or for money))

Sander

### Michael J Zehr

Mar 5, 1999, 3:00:00 AM3/5/99
to
In article <36DFB3E4...@win.tue.nl>,

There might be a position which has no defined equity for money, in
which both players are on the bar against a 5-point board and the
correct cube action is double/take if your opponent is still on the bar
when it's your turn to roll. This could easily lead to 8 cubes in a
row.

However it might well not be a double holding a 64-cube when the score
is -99:-99.

So just to be picky (grin) it's possible to play a 99 point match in one
game with proper cube action... it's just very unlikely.

-Michael J. Zehr

### Robert-Jan Veldhuizen

Mar 6, 1999, 3:00:00 AM3/6/99
to
On Fri, 05 Mar 1999 11:37:24 +0100, Sander van Rijnswou
<san...@win.tue.nl> wrote:

>> Well, just to be picky, if both players know the strategy for a 2pt
>> match and apply it (almost) perfectly, we're effectively talking about a
>> 2-in-1pt match, which is not "fair" for the same reasons as a 99-in-1 is
>> not fair.
>
>Just to be picky, in a 2 point match both players have to double
>CORRECT to get a 2-in-1.

Still pickier: no they don't have to :-) If one doubles while at less
than 30% and the other just takes...

--
Robert-Jan/Zorba