Books

Forum Archive : Books

 Robertie: 501 Essential Backgammon Problems #75

 From: Hardy Hübener Address: webmaster@hardyhuebener.de Date: 5 November 2005 Subject: Robertie - 501 Essential BG Problems - Problem #75 (errata) Forum: rec.games.backgammon Google: dkiac4\$afs\$1@news1.ewetel.de

```After reading Robertie's "501 Essential Backgammon Problems" randomly,
some problems each night, I now started to work my way through the book
more systematically :)

Problem #75 contains an error in the text:

GNU Backgammon  Position ID: bHcwAyC22U4AIA
Match ID   : cIkEAAAAAAAA
+24-23-22-21-20-19------18-17-16-15-14-13-+  O: WHITE
| X     O  O  O  O |   |             O    |
|       O  O  O  O |   |             O    |
|             O  O |   |                  |
|                  |   |                  |
|                  |   |                  |
|                  |BAR|                  |v (Cube: 1)
|                  |   |                  |
|                  |   |                  |
|                  |   |    X             |
|    X  X  X     X |   | X  X           O |
| O  X  X  X     X |   | X  X     X     O |
+-1--2--3--4--5--6-------7--8--9-10-11-12-+  X: BLACK
Pip counts: O 119, X 102

Black (X) rolls 1-1.

Robertie comments:

"This is a great shot, and three of the aces are very clear: 24/23 (to
escape) and 2/1* (2), putting White on the bar. How about the last ace?
A prosaic player would try either 8/7 or 10/9, both of which leave
Black with three builders for the open 5-point, at a cost of one or two
shots from the bar. The ingenious player, however, notices that
duplication allows him to play 8/7! [HE PROBABLY MEANS 7/6 HERE!] At a
cost of three shots (52 and 55) instead of two, Black gets four builders
for the 5-point and three builders for the 2-point, with complete
diversification of point-making numbers. A great play."

1) It should be noted, that Robertie actually recommends 7/6, while 8/7
is printed. (Otherwise 52 would not be a shot and there were no 3
builders for the 2-point.)

2) While Robertie's play is actually very bold, I am not sure whether I
would play 7/6. Rollouts (1296, cubeless, with variance reduction)
seem to indicate, that 7/6 only wins few gammons more than 8/7, while
winning less often and losing more gammons. How would you play the last
ace?

1. Rollout    24/23 8/7 2/1*(2)         Eq.:  +0,214
0,560 0,193 0,002 - 0,440 0,099 0,003
2. Rollout    24/23 7/6 2/1*(2)         Eq.:  +0,171 *(-0,043)*
0,549 0,210 0,002 - 0,451 0,132 0,007

Hardy ;-)
```

 Raccoon  writes: ```With 24/23 2/1*(2), I'd have played the "prosaic" 8/7. Although Robertie writes (correctly) that > three of the aces are very clear 2/1*(2) 8/6 also gives 3 builders for the 2 point and 4 builders for the 5 point. Perhaps that is the prozac play, but it's not a terrible play. I do agree that 24/23 is "clear." 8/7 and 10/9 both give X three builders for the 5 point, but 8/7 is better because X can use the spare without giving up the bar point. The duplication of 54 (bar/20/16* or bar/20 6/2*) after 10/9 is illusory; with 54, O will simply play bar/16*, and 55 is still a great number. After X's play O is 16/36 to fan. When he does X has a stronger double after Robertie's suggested play, 24/23 2/1*(2) 7/6. I recollect that there isn't much discussion in "501" in the checker play problems about anticipated cube action but perhaps that is key to finding the correct play in problem 75. 7/6 also gives X a few more returns in response to O's 23 22 24 53 and 54, and is probably better if O rolls 25 26 21 or 51. 24/23 2/1*(2) 7/6 seems to gain a little on a lot of O's rolls. Your rollout was cubeless; I'll run a couple of cubeful rollouts and post them by and by. ---- GNUBG 0-ply (2-ply cube) rollout at match score 0-0/17 (7776 games): 1. Rollout 8/6 2/1*(2) Eq.: +0.3195 0.5546 0.1908 0.0024 - 0.4454 0.0864 0.0037 2. Rollout 24/23 8/7 2/1*(2) Eq.: +0.3184 ( -0.0011) 0.5608 0.1931 0.0024 - 0.4392 0.0981 0.0037 3. Rollout 24/23 7/6 2/1*(2) Eq.: +0.3127 ( -0.0069) 0.5457 0.2113 0.0024 - 0.4543 0.1340 0.0067 4. Rollout 24/23 10/9 2/1*(2) Eq.: +0.3105 ( -0.0090) 0.5577 0.1852 0.0024 - 0.4423 0.0942 0.0037 ```

 Did you find the information in this article useful?           Do you have any comments you'd like to add?

### Books

Bagai: Classic Backgammon Revisited  (Gregg Cattanach, Feb 2002)
Bagai: Classic Backgammon Revisited #100  (Raccoon, Nov 2004)
Bagai: Classic Backgammon Revisited--Errata  (Jeremy Bagai+, Apr 2005)
Ball: Alpha Backgammon  (James Takahashi+, May 1994)
Ballard & Weaver: Backgammon Openings Book A  (Marty Storer, Jan 2008)
Ballard & Weaver: Backgammon Openings Book A  (Mislav Radica, Nov 2007)
Ballard & Weaver: Backgammon Openings Book A  (Rob Adams+, Oct 2007)
Ballard & Weaver: Backgammon Openings Book A  (Gregg Cattanach, Oct 2007)
Ballard & Weaver: Backgammon Openings Book A  (Neil Kazaross+, Jan 2005)
Ballard & Weaver: Backgammon Openings--Volunteers needed  (Nack Ballard, June 2007)
Barr: Barr on Backgammon  (Walter Swan+, Feb 1996)
Becker: Backgammon for Blood  (Gus, Mar 2003)
Becker: Backgammon for Blood  (PTaber+, June 1999)
Becker: Backgammon for Blood  (Michael Fuhrmann, Aug 1997)
Becker: Backgammon for Blood  (Daniel Murphy, July 1997)
Becker: Backgammon for Blood  (Durf Freund+, May 1994)
Bell: Winning with the Doubling Cube  (&Atilda;˜ystein Johansen+, Apr 2006)
Bell: Winning with the Doubling Cube  (André Nicoulin, Oct 2000)
Bell: Winning with the Doubling Cube  (David Montgomery, May 1999)
Bell: Winning with the Doubling Cube  (Peter Bell, Aug 1998)
Bell: Winning with the Doubling Cube  (Jacques Torrione, Feb 1998)
Bell: Winning with the Doubling Cube  (Robert Scibelli, Dec 1997)
Bell: Winning with the Doubling Cube  (Kevin Bastian, Nov 1997)
Bray: Backgammon for Blood  (Chris Bray, Sept 2007)
Bray: Backgammon to Win  (Chris Bray, June 2007)
Bray: Backgammon to Win, second edition  (Chris Bray, Aug 2012)
Bray: Backgammon--An Independent View  (Chris Bray, May 1998)
Bray: Backgammon--An Independent View Revisited  (Chris Bray+, Jan 2005)
Bray: Second Wind  (Chris Bray, May 2007)
Bray: What Colour is the Wind?  (Chris Bray+, June 2002)
Bray: What Colour is the Wind?--Rerelease  (Chris Bray, Sept 2006)
Brooks: Backgammon's Best Openings and Replies  (Chuck Bower+, Dec 2004)
Clay: Backgammon Winning Strategies  (Michael Strato, Nov 1999)
Clay: Backgammon Winning Strategies  (Gary Wong, Jan 1998)
Cooke & Bradshaw: Backgammon--The Cruelest Game  (Chuck Bower+, Aug 1998)
Cooke & Orléan: Championship Backgammon  (Timothy Chow+, Apr 2011)
Cooke & Orléan: Championship Backgammon  (Marty Storer, Sept 2004)
Cooke: Paradoxes and Probabilities  (Neil Kazaross+, Sept 2004)
Cooke: Paradoxes and Probabilities  (Peter van Arkel+, Sept 2002)
Cooke: Paradoxes and Probabilities  (Donald Kahn, Dec 1998)
Cooke: Paradoxes and Probabilities  (Stephen Turner, Apr 1996)
Corbett: Backgammon Problems  (Stick+, Jan 2008)
Deyong: The Playboy Book of Backgammon  (Shuman Lloyd Lee, Aug 1991)
Dwek: Backgammon for Profit  (Bob Stringer, Sept 2002)
Euler: Everyday Errors in Checker Play  (BaronGossettEulerPhD+, June 2012)
Garal: Fair Backgammon Tournament Rules  (Jakob Garal, June 2007)
Heinrich & Woolsey: New Ideas in Backgammon  (Douglas Zare, Mar 2003)
Heinrich & Woolsey: New Ideas in Backgammon  (Craig E. Groeschel+, Sept 1998)
Heinrich & Woolsey: New Ideas in Backgammon  (David Montgomery, May 1997)
Heyken & Fischer: The Backgammon Handbook  (Martin Fischer, Sept 1998)
Heyken & Fischer: The Backgammon Handbook  (Marina Smith, Feb 1998)
Hickey & Storer: What's Your Game Plan?  (Timothy Chow, May 2011)
Jacoby & Crawford: The Backgammon Book  (Patrick Wilken, Aug 1991)
Kansil: The Backgammon Quiz Book  (Daniel Murphy, July 1997)
Kansil: The Backgammon Quiz Book--Five problems  (Chuck Bower, Oct 1997)
Kennedy & Papazian: Backgammon Master Games  (Ben Fairbank+, Apr 1999)
Kershaw: Backgammon Funfair  (Tom Keith+, July 2012)
Kershaw: Backgammon Funfair  (Peter Bennet, May 2012)
Lamford: 100 Backgammon Puzzles  (Harold Simon+, Oct 2001)
Lamford: 100 Backgammon Puzzles  (Mark Driver, July 2001)
Lamford: 100 Backgammon Puzzles--Snowie analysis  (Michael Schell, Oct 2001)
Lamford: Improve Your Backgammon  (Alef Rosenbaum, May 2003)
Leet: Winning Backgammon  (Ryan Long, Apr 2002)
Leet: Winning Backgammon  (MW Book Review, July 1999)
Lortz: Double ... now: An Authentic Cube Remedy  (Chuck Bower+, Jan 2004)
Mabardi & Luce: Vanity Fair's Backgammon to Win  (Paul Tanenbaum, Feb 1998)
Magriel: Backgammon  (Baldo+, Mar 2004)
Magriel: Backgammon  (Neil Kazaross, July 2003)
Magriel: Backgammon  (Chuck Bower, Nov 1999)
Magriel: Backgammon  (Dean Gay, Sept 1999)
Magriel: Backgammon  (David Montgomery+, Aug 1997)
Magriel: Backgammon--2004 Edition  (Tom Keith+, Dec 2004)
Magriel: Backgammon--GnuBG evaluations  (Randy, July 2008)
Martyn: Phillip Martyn on Backgammon  (Steve Brorens+, Nov 1996)
Munchkin: Gambling Wizards  (Chuck Bower, Aug 2003)
Obolensky & James: Backgammon the Action Game  (Edward D. Collins+, Oct 1999)
Reese & Brinig: Backgammon: The Modern Game  (Al Mirpuri+, Sept 2011)
Robertie: 501 Essential Backgammon Problems  (Paul Epstein, July 2005)
Robertie: 501 Essential Backgammon Problems  (Albert Silver, Nov 2002)
Robertie: 501 Essential Backgammon Problems  (Tore Fredriksen, July 2002)
Robertie: 501 Essential Backgammon Problems  (Erik M Sørensen, May 2000)
Robertie: 501 Essential Backgammon Problems  (Daniel Hollis, May 2000)
Robertie: 501 Essential Backgammon Problems #75  (Hardy Hübener+, Nov 2005)
Robertie: Advanced Backgammon  (Doni+, Jan 2005)
Robertie: Advanced Backgammon  (Scott Steiner+, Sept 2002)
Robertie: Advanced Backgammon  (James Eibisch, Jan 1998)
Robertie: Advanced Backgammon  (Allen R. Adams, Nov 1995)
Robertie: Advanced Backgammon #165  (Peter Grotrian+, Mar 2005)
Robertie: Advanced Backgammon--Errata  (Matt Senecal+, Nov 2004)
Robertie: Advanced Backgammon--JF rollouts  (Øystein Johansen, June 2001)
Robertie: Advanced Backgammon--JF rollouts  (Alexander Nitschke, Feb 1997)
Robertie: Advanced Backgammon--JF rollouts  (Peter Fankhauser, Jan 1996)
Robertie: Backgammon for Winners  (Carl Tait, Aug 1998)
Robertie: Backgammon for Winners  (Gerry Tesauro, Oct 1993)
Robertie: Modern Backgammon  (Mattias+, Apr 2003)
Robertie: Modern Backgammon  (Gregg Cattanach, Oct 2002)
Robertie: Modern Backgammon  (Frank Mazza+, May 2002)
Robertie: Reno 1986  (AH+, Aug 2007)
Shiina: Cube Action 1000  (Mochy, Feb 2013)
Steed: Backgammon: The Meanest Game  (Albert Steg, Aug 1998)
Stern: Backgammon: The Quick Course to Winning Play  (Mark Driver, May 2001)
Storer: Backgammon Praxis  (Chase+, Apr 2007)
Storer: Backgammon Praxis  (Marty Storer+, May 2004)
Thorne's Backgammon Tactics (Reprint)  (Sam Sloan, July 2012)
Tremaine: Amazing Book of Backgammon  (Jim Wallace, Feb 1998)
Trice: Backgammon Boot Camp--2nd edition  (Jeremy Bagai+, June 2007)
Tzannes brothers: Backgammon Games and Strategies  (Mark Driver, Apr 2001)
Tzannes brothers: Backgammon Games and Strategies  (Albert Steg, May 1994)
Tzannes brothers: How Good Are You at Backgammon?  (Mark Driver, July 2001)
Wiggins: Boards, Blots, and Double Shots  (Ned Cross+, Mar 2004)
Williams: Backgammon Live in London  (Sean Williams+, June 2008)
Woolsey & Beadles: 52 Great Backgammon Tips  (Paul Epstein+, Dec 2007)
Woolsey & Beadles: 52 Great Backgammon Tips  (Mislav Radica+, Oct 2007)
Woolsey & Jones: Understanding Backgammon  (Jon Nall+, Feb 2004)
Woolsey: How to Play Tournament Backgammon  (John Bazigos, Oct 1994)
Woolsey: The Backgammon Encyclopedia Vol 1  (Dean Gay+, Feb 2004)

 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

Return to:  Backgammon Galore : Forum Archive Main Page