I've just completed an XG study of Wiggins's book Boards, Blots, and Double Shots and have posted the results on my website.
The most interesting position in the book, in my opinion, is Position 14, shown here:
| White | 140 |
|---|---|
| |
| Blue | 142 |
| GNUBg Id: 2J2FATBsG8UBMA:cIkYAAAAAAAA XGID=-b-BBBB--AA-bC--ab-ccb--B-:0:0:1:61:0:0:0:0:10 | |
I'd also like to comment on Position 3, shown below, because it illustrates a common confusion regarding the Jacoby rule.
| White | 129 |
|---|---|
| |
| Blue | 117 |
| GNUBg Id: ZlvBMALbOMgDIA:cIkMAAAAAAAA XGID=-BBB-aC-b--AbD---aabbb-bA-:0:0:1:31:0:0:0:0:10 | |
It is sometimes stated that the Jacoby rule speeds up games but at the cost of eliminating an element of skill from the game. The point I wish to make is that neither statement is true, at least at sufficiently high skill levels.
In Position 3 above, what is the right way to think about the hitting play 13/10 6/5*, if the Jacoby rule is in effect? If Blue plays 13/10 6/5*, then a weak player (as White) will be unlikely to even consider doubling from the bar. If White hits and Blue rolls poorly, then she may play on for a while. If things continue to go well, she may eventually remember the cube and the Jacoby rule and cash. Thus the game will be "sped up" because it will be cut short rather than played out to the end for a possible gammon. So far everything seems to be in accord with the conventional wisdom.
However, let's now imagine that Blue and White are world-class players. Then White will recognize that hitting from the bar will often give her a position that is too good to double. If the Jacoby rule is in play, then the effect will be to induce White to double from the bar, in order to reap the full benefit of those variations. Without Jacoby, White would not double from the bar. So it is far from clear that the game will be "sped up" when the Jacoby rule is in force; in fact, it's conceivable to me that the game will end sooner on average when the Jacoby rule is not in effect, because it's not too unlikely that if White hits, she will play on for just a couple of rolls and then cash.
As for whether the Jacoby rule eliminates an element of skill from the game, it surely requires no less skill to decide whether to double from the bar when the Jacoby rule is in effect than when it is not in effect. Moreover, consider the skill involved in Blue's decision whether to play 13/10 6/5*. With Jacoby in effect, 13/10 6/5* forces White into an inefficient double from the bar, and is therefore more attractive than the play would be if there were no Jacoby rule. Again, it surely requires no less skill to assess the merits of 13/10 6/5* when the Jacoby rule is in effect than when it is not.