Backgammon Boot Camp: Errors
Walter Trice began work on what would become Backgammon Boot Camp in 2001, using the best technology available: Snowie 3. Times have changed, and so have bots. The following table shows all twenty-six positions where the current best bot, eXtreme Gammon 2, contradicts the old result.
Note that fifteen of the twenty-six errors concern backgames (Chapter 5). XG2 is significantly stronger in this phase of the game than any prior bot. Eight of the fifteen backgame positions are cube actions, and in all eight cases, the backgame player is stronger than previously thought. Four initial cubes against backgames turn out to be no-doubles. Three backgame passes turn out to be takes. And one take after the backgamer has hit a shot turns out to be a big pass.
Only ten errors felt significant enough to warrant additions to the original text. This judgment turned out to correspond to an equity difference of .04 or greater. These table entries are in bold.
This table is new to the fourth printing of Boot Camp. If you own an earlier edition, print out a formatted copy to paste in your book.
|Pos #||Best Play||Error Size||Note|
|1-01||10/6 9/4.||0.006||Better for the most likely variation: a close race.|
|1-02||13/10 6/4||0.016||No need to strip the 8 point.|
|1-17||Bar 23* 17/12||0.016||6/1 is great if you get hit on the ace; bad if you get hit on the deuce.|
|1-21||6/1 5/1||0.045||More costly to expose blots when approaching a cube-turn. Close decision if already cubed.|
|2-05||20/15(2) 6/1*(2)||0.037||Buriel is not so bad against an advanced anchor. Where else can your stacked checkers go?|
|2-15b||5/4 5/2||0.012||4/3*/0 buys only 3 additional gammons for 3 additional losses. Not worthwhile for money.|
|2-25||21/16||0.049||Duplication is wrong theme, as Black does not mind being hit. But he does mind being hit with 55.|
|4-03||Pass||0.010||Bare take reference is actually bare pass.|
|5-01||No Double||0.035||Close No Double against backgame|
|5-04||No Double||0.038||Close No Double against backgame|
|5-07 (31)||13/9||0.030||The 2-3 backgame better than 2-4. The midpoint is not so important|
|5-07 (55)||23/18(2) 13/3||0.006||Keeping the 8 is more valuable than keeping the midpoint.|
|5-09||B/23 8/4* 6/4||0.023||Not yet comitted to backgame.|
|5-20||B/20 13/9||0.020||Most pure play for building prime.|
|5-21||B/22 24/22||0.058||The triple anchor is stronger than was previosuly understood.|
|5-22||No Double||0.017||Close No Double against backgame|
|5-25||Take||0.078||2-3 backgame with timing can Take|
|5-26||No Double||0.014||Close No Double against backgame|
|5-28||Take||0.052||1-4 backgame with timing can Take|
|5-38||No Double||0.095||Volitility is super low. Since this is actually a take, no reason to double.|
|5-46||Pass||0.169||Trice was right to find the Snowie rollout Take "very surprising."|
|5-48||6/4 6/1||0.088||The prime is White's strongest asset.|
|5-51||16/8||0.065||No need to break anchor. Don't make the ace!|
|6-09||Redouble||0.118||Huge market loss after a 6.|
|7-08||Take||0.001||Close Pass becomes close Take|
|7-10||Too Good||0.022||Close Cash becomes close Too Good.|