in the position below at DMP i played 13/12 10/4 leaving no blots, which was a big blunder. the bot prefers 13/7 6/5, leaving 4 blots. can someone explain please?

It’s DMP - gammons and backgammons don’t matter. All that matters is winning the game. You are way behind in the race. There is no way you can win this game without hitting an opposing checker and containing it in your side of the board until you can catch up. In order to contain a checker you will need to make the 7 point and the 5 point. The move suggested starts both of these important points.

Getting hit is not really a problem. You’re already behind; getting hit leaves you still behind. The worst case here is that you do NOT get hit, but cannot contain your opponent’s back checker. He maintains his prime and you are forced to keep moving your checkers forward. Eventually you will crash your board waiting for your chance to hit, and if you do your 6 and 5 points will be open and your opponent will escape and win.

This concept is called timing. Simply put getting hit and (hopefully) spending a few moves stuck on the bar would improve your timing. You would have a better chance of having a strong board to contain a hit checker if you slow down your forward moves. Having more checkers back also allows you to wait longer before being forced to break contact. Even if your opponent is down to 1 checker, hitting that checker and closing it out gives you a chance to win. Should you close out his last two checkers, you will actually be a favorite to win.

Don’t get me wrong - you are in bad shape here. However having more checkers sent back actually might help your winning chances later in the game. If gammons mattered, this probably would not apply, and a safer move like you suggested might be better. Having more checkers back significantly increases your chance of being gammoned.

thanks for your answer, the move makes sense now. how do you judge timing in an ace-point game? pips, crossovers, number of checkers to play?

I guess you meant the 7 and 5 points will be open?

Actually I was referring to a hypothetical future position where his board crashes and he is forced to open his high points allowing any blots he might hit an escape route, so I did mean open 5 and 6 points. The 7 would obviously be open too in such a position, but that would not affect his opponent being able to enter from the bar.

A combination of these. You also look at your ability to recycle your back checkers. Normally that third checker on the ace point represents a good bit of timing, but not in this case since it cannot move. If it had some escape numbers (such as your opponent not having his bar point made) then your timing would be much better.

Getting hit in this position is actually a bit risky from a timing standpoint for precisely this reason. If you get hit, you want to dance, not enter quickly. If you enter quickly, you lose the timing you’d have had if your checker had not been hit. If you dance though your opponent should start to break his prime allowing you to escape checkers and keep your timing. You should be working to build your home board to contain the checker(s) you will hopefully hit.