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Robertie: Advanced Backgammon--JF rollouts
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Brian Sheppard wrote:
> JF misevaluates Problem 127 ("Kauder's Paradox"). In this position
> JF thinks White is a big underdog, and actually considers Black to have
> over 50% chance of winning a gammon! This is quite wrong. Actually White
> is a clear favorite. If you take JF's side in that proposition, you will
> lose about 1.33 points per game, since JF drops a double it should beaver.
Ok, this is a position which JellyFish simply doesn't understand.
JellyFish's by far biggest weakness is the misunderstanding of the value
of outfield primes and the lack of a technique to build such a prime and
roll it home.
But as far as I can assess the problems there was no other position with
a large error from the Level6 rollouts (and I think I'm not too bad for
this job).
You're right with these 1.33 points per game, but I'm sure there is no
other case with an error greater than 0.2 points per game even in the
backgame section.
> You might think that a position like Kauder's Paradox is too extreme to
> be relevant to practical play. Actually, that is not true. JF will
> happily hit all 15 of your men any time it has the chance. If you happen
> to get a backgame against JF, you can make hara-kiri plays until all your
> men are hit, then build an outer-table prime after hitting JF. Your money
> game equity is reasonable only because JF incorrectly beavers your double
> after you complete the prime.
>
> On the other side of the ledger, I have found a position
> where Robertie seems to be going badly wrong (I recall
> that number 80 is such a position).
Problem 80 probably is wrong by Robertie (0.096 difference in the
rollout).
I can tell you some problems where Robertie is really badly wrong:
Problem 48 (which is a clear take and not a pass)
Problem 52 (22/18 is clear best, not even mentioned by Robertie)
Problem 63 (another clear take)
Problem 84 (equity difference 0.55! according to Level6 rollout and I
believe this is not way wrong)
Problem 99 (clear pass, not a take)
Problem 149, 177a (both no double, Robertie would double)
Problem 199b (no double, Robertie would pass!)
Problem 252 (clear take, not a pass)
Problem 332 (no double, Robertie would double)
These errors have all equity losses of at least 0.2 (except Problem 52
with 0.17). There are 16 more problems with errors greater than 0.1 and
a total of 99 problems (out of 451) with an error greater than 0.01
(according to Level6 rollouts). I know that in some cases the rollouts
could be wrong and Robertie could be right, or the error of Robertie is
less severe than indicated, but there are many problems with wrong
solutions.
> My conclusion is that you place way too much faith in JF.
I sound like a worshipper of JellyFish Level6 rollouts :-)
But I can assure you that this is not the case. I know of some
weaknesses which can lead to wrong rollout results. Containing a hit
checker in extreme cases is a weakness of JellyFish which leads to wrong
rollout results in some backgames and some endgames.
Best greetings
Alexander (acey_deucey in FIBS)
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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)
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- 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)
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- 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)
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