Cash game, centred cube (yes, I missed the double preceding this roll). Red to play 61.

Hitting 8/2* 7/6 is a huge blunder here, but I'm not sure why, especially with the blot in his board. Seems like I've got plenty of ammunition to shoot for a close-out, and having to leave a shot anyway makes it seem even more obvious. Clearly I'm missing something conceptually about this position...

My first reaction is to note that you're giving up an asset to launch your attack. This neither makes the attack right nor wrong, but you're giving up something to play out this blitz. You've got white's blot trapped behind a 4 prime, needing two rolls to escape. By making your play, you're giving up that 4 prime. That is a high price to pay (plus losing a lot in the race if he hits coming off the bar), which means that you had better be getting something just as big in return.

This same idea of considering the cost applies to white as well. If you leave your shot in front of a stripped point, then in order for him to hit he must give up the point. If you attack in the home board, he attacks you at no cost to himself. This is not really the position you want to be in.

As a bonus, white needs a 2 to advance his back checker. By duplicating 2s, you make it harder for white to hit AND advance. Given that white has no spares anywhere, it might be right for him to pass on the hit so that he can advance that rear checker (which means that blot is much safer than it first appears).

Finally, I think you *want* white to move checkers around (which he can't do when he's on the bar). This goes back to the idea that he has no spares. If white doesn't hit, he's almost certainly going to have to break one of those anchors. When he breaks, you're often going to have a shot at sending a SECOND checker back, and this is a huge win for you.

You have a gapped 5-prime with the gap in the very front, which is the best place to have one. This is a powerful forward structure, and it's a quite large concession to break it. Meanwhile you only have 3 home board points, so an attack isn't especially appealing.

Given that White's forward structure isn't hugely threatening, you should look for any other reasonable move, and just hope to scramble home sooner or later.

Ok, that makes sense.

Here's another blitz position I encountered this morning that I was surprised to see required a hit & a slot! Sort of the opposite theme from the first position, in that the correct play requires maximum aggression.

Red to play 53.

Hitting with 6/1* is quite clear, but I was surprised to see the slotting play by breaking the 8 point. So we're not only breaking an asset, we're taking on additional return-shot risk! This play struck me as a bit too loose... any sequence where he enters with a 5 seems immediately dangerous, especially when 2 of my 3 entering numbers (1 & 2) are also my re-hitting numbers (if he stays on my 5pt), and even hitting him a second time could leave yet another double shot if I can't cover the blot on the ace pt...

So what is the key to this play? More generally, I would be curious to understand under what circumstances in a blitz you want to attack AND slot an additional inner-board point (thereby leaving a double-shot).

Well this is an interesting contrast, because let's say you make the Ace point but still have the gap on the 5-point. Now you again have a broken 5-prime (in a sense) but the gap is at the back, which is the WORST place to have it. Any checker that enters will have little problem leaping, or Villain can keep the checker there for outfield coverage, depending on the exact position.

In practice, with two men to scramble home, making the 5-point becomes very important, and your chances of making it go way down if you remove one of your builders with the 3, so you slot it and hope for the best. It might actually be better if you didn't have to play the 3. But when the choice is to either slot or leave it open permanently, I think it's pretty clear what to do if you are going to hit at all. The other option is to play safe and get the back men moving and hope to scramble home, but what fun is that?

As far as your other question, this sort of position is quite rare in my experience.

Thanks, that makes sense about not wanting to lose a builder for the 5 point, and slotting the 5 point being the only way of doing it. As you pointed out, bit of an unusual situation.

Perhaps the most valuable lesson from this obscure position is that, if you're behind in the race but you have the safety of an anchor, it's better to risk falling further behind than losing one of your last builders for a key home-board point (especially if it's the 5 point).

Lately I'm often struggling to know what to do when I have an awkward roll and am faced with the choice of either leaving an extra shot and/or breaking up some asset, vs. permanently moving a builder out of play (or, earlier on, slotting a deep home-board point). These sorts of choices have made up a disproportionate number of my blunders lately, and I haven't yet been able to figure out some simple heuristics for handling these situations.

That's because it's a complicated game. There's a lot to consider, and I don't think any simple heuristic will get you very far.

There are two ways to learn about a position.

One way is to play out the position a whole bunch of times to see what happens.

The other is to change the position to one that is just slightly different and analyze the new situation. The idea behind this is that you'll start to see what's important to a position and what's not so important. If you do this enough times, you'll start to see patterns developing and you can start to build your heuristics from there (there won't be a simple rule to cover ALL cases, but you'll see enough to give you a solid basis of considerations that will guide your decisions).

Yeah. This.

Also, OP, one of the most important habits to develop is to consider all variables. What is the status of the race? Who has the most home board points? The most runners? etc. etc. eg "Look at the whole board". A sometimes trivial change can make a big difference.

The problems Bill Robertie has been posting are good for this sort of thing, and seeing the reasoning that various responders use.

Making a small change to the position and seeing how this affects the result is a very important idea for understanding what's going on. (Bots allow us to do this comfortably, whereas in the old days no one had the time.) But there's another important reason involved here.

Some backgammon position are what I call "freaks". That is, closely related positions all show one clear theme, but in the exact position you've got, because of the precise arrangement of all the checkers, a weird-looking play turns out to be correct. The freak position may actually have nothing of general importance to teach us, but we can't know that unless we set up and roll out related positions to see what's really going on.

Having said that, I don't think your second position fits the freak category. Black needs the 5-point to win, and he's unlikely to make it naturally, so slotting is important. The key features of the position are Black's big stack on the 6-point (which makes waiting unappealing) and the lack of connection between his front and rear checkers (which forces him to try and close his board before starting the long march around.)

Two great positions, by the way. Very instructive.