I was tossing up between 13/11 and 8/6, choosing 8/6 but thinking it would be close between the two options. I was very surprised to see that it was far from close and that there were 3 other moves that were better than my choice.

I understand now why 13/11 is better than 8/6 but I'm at a loss to explain why moves like bar/18 or 24/22 come out better too. It appears that the engine thinks that 8/6 harms our position as I can't see the benefit of bar/18 or 24/22.

Any thoughts?

11/9
4 and 7 point potential

bar/18
don't put checker on point adversary wants. (Robertie, p.xxx) plus, being hit can be favourable for making more advanced anchor.

24/22
remarkable. in any way, there is not much blitz opportunity, and if covered afterwards, better than defensive 24point. still, something for XG in my opinion

13/11
blots create the commitment to get rid of them.(Robertie, p.xxx) 3 blots means approaching some unwritten threshold

Points are good, so you need a very good reason not to play 13/11. 8/6 just doesn't do anything -- you lose a builder for the 7-point to create one for the 4-point.

My guess is along the lines of Robertie.

The "builder" on the six point is an illusion. The bar point is the point you want here, so the spare on the 8 is useful while you are sorta killing this builder by going to the normal looking six point.

As to the other plays there may be some duplication at work. Bar/18 is counterintuitive but does duplicate opponent's sixes and threes, which he desperately needs to move off the ace point. three men on ace point is really bad.

Bar/20, 24/22 also duplicates attacking 5's which hit on 5 point and 3 point and the 3's hit on the 5 point but also advance off the ace point on the other side of the board. It could also be that it is really hard for opponent to attack and escape at the same time - also bearing in mind that a single return hit from you is essentially fatal.

But I think the main reason is that 13/11 is totally safe and keeps the builder on the 8 point in play to make the bar point naturally.

One minor addendum I would add to the major points made above concerns the second-best play, 24/22.

Moving up freezes your opponent's stripped 8pt. If he wants to attack from there when he rolls a 3, he will often have to leave a vulnerable blot behind. The fact that 5 is duplicated means that 55 is the only roll you are risking.

In case your opponent rolls a 5, and hits loose on your 20pt, you will be glad to have moved up. From the bar, you will have 5s to hit, and 3s make an anchor. Contrast this with the anchor offerred by aces when you do not move up.