The moves I can see here as being legitimate plays are || 8/3* || 6/3* 3/1* || 11/9 6/3* || 24/22 6/3* and 24/22 24/21 as a control.

Black is behind 5 pips in the race and he'd like to attack white and gain the race lead. 8/3* puts white on the bar and if he isn't hit next roll he can cover with a checker on the 6 or maybe use it to make the 2 or 1 next roll and possibly hit again. 11/9 6/3* and 24/22 6/3* create some flexibility on other sides of the board but 24/22 6/3* leaves black with the checker on the 8 to help his checker on the 3, not as ideal as having the 6 checker. However, that flexibility might be worth more.

But what about the double hit? Black would have no direct cover should white fan and may not have a cover for a while. I don't think black is that worried about being hit here as white's board isn't that threatening but white is starting to brew up some trouble and black could find himself in a sticky situation if he gets hit, especially if his 2 back checkers are still on the 1. Not sure what the best move is here.

As for the control 24/22 24/21 it just doesn't do enough and doesn't take advantage of attacking white's split checkers.

One well-played sequence that reaches this position is:

Black 21-Slot: 13/11, 6/5
White 51-split: 24/23, 13/8

Black 21-Near: 13/11, 6/5
White 41-Split: 23/22, 13/9

Black 32-?

The first choice is whether to hit at all. That’s an easy one, however. Black has the better board, and White has a builder on his 9pt which gives him many point-making combinations if left to his own devices. Hitting takes the initiative away from White, and fits perfectly with Black’s game plan.

The next question is whether to hit twice. That’s relatively easy as well. Hitting twice puts a checker out of position on the 1pt, for which Black has no direct covers. Black has decent priming chances here. Changing to an attacking game plan is not necessary. Because Black has made his 5pt, the two Black checkers on the 11pt are not targeting an inner-board point. That means they are not “in the zone,” which leaves Black with only eight checkers that are. Priming—not blitzing—is the natural game plan for Black.

Now the problem is much easier. After hitting with the 3, Black’s next question is whether to bring another checker within direct range, or whether to split his checkers on the far side. Splitting threatens the White checker on the 16pt, and may give Black a good 6 to play from the bar in case he is hit. Unfortunately, splitting does nothing to further Black’s priming effort. After splitting, Black would be left with 5 as the only direct cover for his blot. For that reason, I rejected splitting.

Finally, there are two ways to bring a checker within range of the 3pt. Black can break the largely redundant 11pt to bring a checker down to the 9pt, or else he can play 8/6 to resupply the stripped 6pt. For me, the stripped 6pt is what tips the balance. It was the primary reason I chose 8/3* instead of 11/9 6/3*. Black gets two direct covers for his blot, and does not have to leave any fly shots (and/or double hits) with 54 and 63. In addition, although owning the 5pt reduces the value of the 11pt, the 11pt is not completely useless. With an alternative as good as 8/6, there is no compelling reason to abandon it.

A request for Ender1204: Thanks for posting another interesting position. If you can, please post the XGID and/or GnuBg ID along with your board diagrams. In eXtreme Gammon, press Shift+Ctrl+C to copy the XGID. Next, switch to TwoPlusTwo and press Ctrl+V to paste it in. Thanks.

XGID=-a-a-BC-C--BcC--ad-e----B-:0:0:1:32:0:0:0:0:10

Mike

Variation - Black to Play 3-2

XGID=-a-a-BD-B--BcC--ad-e----B-:0:0:1:32:0:0:0:0:10

After posting, I put your position to the bot and created this variation to test out some the ideas in my post above. Not all of them fared well!

What is the best play here, and more importantly, why? How can we distinguish between the two positions?

Mike

The biggest hindrance against the double hit in my original position was lack of direct cover. However, in this position we have an extra checker on the 6 point which gives us 5s, 7s, 10s, 12s to cover. I think that this pushes the double hit over the edge equity wise making it the correct play. Since black gains a lot of tempo from the double hit, especially if he isn't hit back, he can spend the next move creating a more flexible position in the other quadrants.

Over the board (for the 2nd position), I would certainly prefer 11/9 6/3* to 6/3*/1*. I don't want to commit to blitzing now, I would prefer keeping the door open for priming.