Below is a nacbrac summary for XGR++ evaluations ("&e) of the four positions mentioned. As Zoe suggests, the contrast of the two middle positions is the one worth remembering.
........64P-63S-66 [O B148]
........53P-63S-66 [O B19 Z192]
........42P-63S-66 [B O28 Z123]
........31P-63S-66 [B Z56 O62]
It may be worth noting that Zoe used only XGR+ for the evaluation of 42P-63S-66, which resulted in the somewhat different-margined [O B31 Z132] (though the ranking of plays is the same).
Here are XGR++ evaluations when we replace 63S with 62S (i.e., move the opponent's builder from her 10pt to her 11pt). In the case of 53P-62S-66, I've included a detailed 15k rollout result at the bottom of this e-mail (which is still TCTC).
........64P-62S-66 [O B152] Even though 64S should not be played as a reply against the point-making openers, I've included XGR++ evals for anyone interested in making theoretical comparisons:
........64P-64S-66 [O B132] For this type of "knockout punch" position, it is worth mentioning that in a match, where the Jacoby rule is not in effect, the blitzing play of O has more merit than when playing for money (where Jacoby IS in effect, and therefore blitzing overkill can apply). I'd guess this effect to be as much as.03. In other words, if applied to match play, O might gain (relative to B) say between 20 and 40 thousandths in each of the above evaluations.
Finally, for those who might not know, at the score of gammon go (e.g.,–2–1 Crawford) the blitzing play of O is massively best (at least a double or triple wipeout) in all of the above positions. It is even best in the more basic second-roll positions, when one's only inside point is the 6pt. To wit, here are XGR++ evals:
........62S-66 g[O B68] Key: O = Outer (13/7*/1*(2), also can be P = Point), B = Both (24/18(2) 13/7(2)), Z = reverse split 3:1 (24/18 13/7*(3)).
Nactation tutorial • explanation of nacbracs • nacubracs (nacbracs for cube actions) I delayed sending this message until the tied rollout below reached 15k (and decided that was enough CPU). As I was about to click on "post message," I noticed that in the meantime Mike Mannon has posted a wonderful (XGR++ eval) 3-by-4 crosstable that includes both Jacoby and non-Jacoby data.
Nack
53P-62S-66 ..[B=O] "<=15
........53P-62S-66 [O B5 Z182], rollout is [B=O] "<=15
........42P-62S-66 [B O48 Z161]
........31P-62S-66 [B O62 Z76]
........53P-64S-66 [B O3 Z166]
........42P-64S-66 [B O38 Z160]
........31P-64S-66 [B O58 Z82]
........63S-66 g[O B88]
........64S-66 g[O B73]
White is Player 2
score: 0
pip: 159 Unlimited Game
Jacoby Beaver pip: 159
score: 0
Blue is Player 1 XGID=-a-B--DaB---dEa--c-e----B-:0:0:1:66:0:0:3:0:10 1. Rollout1 24/18(2) 13/7*(2) eq: +0.852 Player:
Opponent:68.95% (G:22.46% B:1.00%)
31.05% (G:5.92% B:0.23%)Conf.: ± 0.004 (+0.848...+0.857) - [57.4%]
Duration: 1 hour 48 minutes 2. Rollout1 13/7*(2) 7/1*(2) eq: +0.852 (0.000) Player:
Opponent:67.16% (G:39.55% B:1.24%)
32.84% (G:7.33% B:0.34%)Conf.: ± 0.003 (+0.849...+0.855) - [42.6%]
Duration: 31 minutes 40 seconds 1 15552 Games rolled with Variance Reduction.
Dice Seed: 13465026
Moves: 3-ply, cube decisions: XG Roller