Question:
5-1?
Option 1: 21/15
votes: 8
Option 2: 21/16 8/7
votes: 0
Option 3: 21/16 6/5
votes: 0
Option 4: 13/8 6/5
votes: 0
Option 5: 13/7
votes: 0
Option 6: 8/3 6/5
votes: 0
Option 7: 8/2
votes: 0
A couple of nexts: the Herd didn't double and rolled a 6-5. We hit dorbel's blot 21/15* and continue to make the tenpoint with the checker, 15/10.
dorbel rolled a 4-3 from the bar, perfect to make the anchor B/21 24/21.
The herd now rolls a 5-1.
XGID=----bBC-C-B-eD---b-ccA----:0:0:1:51:0:0:0:5:10
Spoiler
21/15 a trial run - and to leave the 'impact zone'
Spoiler
If we had rolled 6-1 I'd be hard pressed to decide whether to prime or run, but this is easy. Escape the runner with the five, and since I don't see aything better to do with the one, kee moving.
21/15
Spoiler
I simply try to clear the blot now. 21/15. 21/14, 6/5 gives 1 shot less, but all shots of the midpoint, while 21/15 gives dorbel
2 shots of the anchor.
XG Roller+ analysis
Spoiler
1. XG Roller+ 21/15 eq:+0,315
Player : 61,47% (G:5,17% B:0,14%)
Opponent: 38,53% (G:6,38% B:0,13%)
2. XG Roller+ 21/16 6/5 eq:+0,293 (-0,021)
Player : 61,03% (G:4,92% B:0,15%)
Opponent: 38,97% (G:6,82% B:0,16%)
3. XG Roller+ 21/16 8/7 eq:+0,155 (-0,160)
Player : 56,70% (G:6,64% B:0,24%)
Opponent: 43,30% (G:9,28% B:0,29%)
eXtreme Gammon Version: 1.14, MET: Rockwell-Kazaross
As gumpi pointed out, moving from 16 to 15 with the one walks into the two 6-5 indirects shot from the anchor (funny enough, this actually hit us), whereas the 6-6 indirect shot to the 16 point is blocked, so it's two extra shots. From the midpoint however, 16/15 leaves one less shot. Overall, 21/16 6/5 leaves one less shot.
It's still right to play 21/15, by a small margin, I suppose mainly because of three things: we'd rather see dorbel break an anchor to hit than to simply hit from the midpoint; when missed we're probably happier with the runner on the 15pt (easier to get safe and more useful as a builder); and 6/5 puts the spare in a worse position.