Forum Archive : Opening Rolls

Opening 62: Could running be best? From:   Gary Wong Address:   gary@cs.auckland.ac.nz Date:   24 September 1997 Subject:   Re: Opening Rolls Rollouts JellyFish Ver 3.0 Forum:   rec.games.backgammon Google:   iey3emvh1zu.fsf@cs20.cs.auckland.ac.nz Midas wrote: > For those of you interested I've rolled out all the opening moves top > contenders. Trials 1296 Standard Deviations 0.008. I'm not sure of the > statistical relevance of the data with this S.D. but they,re here for > your perusal. Thanks for that article. One thing surprises me a bit though, in the results for 62: > Top moves marked with * > > Dice Move Move L7 EV L6 Roll > 62 24/18 13/11 +.010 +.006 > 62* 24/16 -.003 +.008 > 62 13/5 -.020 -.015 > 62 24/18 24/22 -.041 -.042 Why on earth is JF so eager to play 24/16 (and similar results running to the outfield on 63 and 64)? It even ranks it better than 24/18 13/11 (though admittedly the distinction is lost in the statistical noise). The way I see it: Advantages of 24/18 13/11: * 24/18 leaves the back men in communication (16 return shots on the bar point; only 4 on the 9 point). * Even if the blot on the 9 point is missed after 24/16, you'll be scrambling to safety it next roll, reducing your mobility. * 24/18 leaves good chances of anchoring on the opponent's bar point; 24/16 gives up anchoring for now. * 24/18 13/11 gives a spare builder for the 5 point; 24/16 doesn't put a man anywhere useful (what's the use of being on your opponent's 9 point?) * 24/18 gives better outfield coverage; it protects against the opponent bringing builders to his 9, 10 or 11 points (24/16 only protects the 10 and 11 points) Advantage of 24/16: * Only gives your opponent 14 shots at your blot on his 9 point (2 of his rolls make the 9 point), instead of 26 shots on the bar point (6 make it) Are the reduced shots on the runner really worth giving up all the advantages of 24/18 13/11? Let's see what the outcomes of the next two rolls are: 24/16 24/18 Blot hit, return hit (best) 48 320 Blot missed (good) 792 360 Blot hit, no return hit (bad) 384 400 Blot pointed on (worst) 72 216 ---- ---- 1296 1296 Hard to say whether the chance of hitting back with 24/18 is worth the risk of him making his bar point on your head. There's no doubt that 24/18 increases the complexity of the game, which must make it a better choice against a weaker player. I'd tend to play 24/18 anyway, and it puzzles me that Jellyfish favours 24/16 in the rollouts. Does it see something there I'm missing? What do other humans think? Cheers, Gary (GaryW on FIBS).   Did you find the information in this article useful?           Do you have any comments you'd like to add?

 

Opening Rolls

At different match scores  (Louis Nardy Pillards, July 2002) 

Average advantage of winning opening roll  (Chuck Bower, Oct 1998) 

Choosing a strategy  (Daniel Murphy, June 2001) 

Early game rule of thumb  (Rich Munitz, Feb 2009) 

Factors to consider  (Kit Woolsey, July 1994) 

How computers play  (Kit Woolsey, Mar 1995) 

Magriel's Chapter 5  (Hayden Alfano+, May 2006) 

Mloner vs Jellyfish  (Kit Woolsey, Dec 1995) 

Nactating a whole game  (Nack Ballard+, Jan 2011) 

Nactation  (Jim Stutz+, June 2010) 

Nactation overview  (Nack Ballard, Oct 2009) 

Nactation--Why use it?  (leobueno+, Jan 2011) 

Opening 1's: Split or slot?  (Douglas Zare, Dec 2003) 

Opening 21: Rollout  (Stick, Mar 2006) 

Opening 21: Split or slot?  (Dick Adams+, Dec 2003) 

Opening 32: Rollout  (Stick, Feb 2006) 

Opening 43: In GOL online match  (Raccoon+, Feb 2004) 

Opening 43: Pros and cons  (Stick+, Jan 2006) 

Opening 43: Which split is better?  (Peter Backgren+, Aug 2000) 

Opening 43: Which split is better?  (Michael J. Zehr+, Mar 1996) 

Opening 51: Rollout  (Stick, Feb 2006) 

Opening 52: Merits of splitting  (Peter Bell, Apr 1995) 

Opening 53: Magriel's recommendation  (George Parker+, July 1997) 

Opening 53: Split to 21?  (Alex Zamanian, Aug 2000) 

Opening 53: Why make the three point?  (Kit Woolsey+, Feb 1996) 

Opening 6's: Slot the bar point?  (Chuck Bower+, Feb 2000) 

Opening 6's: Slot the bar point?  (David Montgomery, June 1995) 

Opening 62: Could running be best?  (Gary Wong, Sept 1997) 

Opening 62: Split, run, or slot?  (Chuck Bower, May 1997) 

Opening 63: Middle Eastern split?  (Mark+, Apr 2002) 

Opening 63: Slot the four point?  (Dennis Cartwright+, Mar 2002) 

Opening 64: Make the two point?  (William Hill+, Jan 1998) 

Opening 64: Make the two point?  (Darse Billings, Feb 1995) 

Opening 64: Rollout  (Peter Grotrian, Jan 2006) 

Opening 64: Split to 20?  (Peter Bell, June 1995) 

Opening 64: Three choices  (Brian Sheppard, July 1997) 

Opening 65: Becker on lover's leap  (Jeffrey Spiegler+, Aug 1991) 

Opening 65: Computer rankings  (Chuck Bower, Jan 1997) 

Opening rolls ranked  (Arthur+, Apr 2005) 

Rollouts of opening 21 and replies  (Alexander Nitschke, Oct 1997) 

Rollouts of openings  (Tom Keith+, Jan 2006) 

Rollouts: Expert Backgammon  (Tom Fahland, Aug 1994) 

Rollouts: Jellyfish 3.0  (Midas+, Sept 1997) 

Rollouts: Jellyfish 3.0 level 6  (Chuck Bower, Feb 1999) 

Rollouts: Snowie 4.1  (Rene Cerutti, Apr 2004) 

Slotting the four point  (Joe Loria+, Oct 1999) 

Snowie's openers and replies  (rcerutti, Feb 1999) 

Splitting versus building  (Dave Slayton+, Aug 2000) 

Splitting versus slotting  (Daniel Murphy, Apr 2001) 

Splitting versus slotting  (Daniel Murphy, Sept 1997) 

Trice's rankings  (Marty Storer, Feb 1992) 

From GammOnLine         Long message         Recommended reading         Recent addition

 

Book Suggestions Books Cheating Chouettes Computer Dice Cube Handling Cube Handling in Races Equipment Etiquette Extreme Gammon Fun and frustration GNU Backgammon History Jellyfish Learning Luck versus Skill Magazines & E-zines Match Archives Match Equities Match Play Match Play at 2-away/2-away Miscellaneous Opening Rolls Pip Counting Play Sites Probability and Statistics Programming Propositions Puzzles Ratings Rollouts Rules Rulings Snowie Software Source Code Strategy--Backgames Strategy--Bearing Off Strategy--Checker play Terminology Theory Tournaments Uncategorized Variations