A cute play. 13/4 is obvious and OK, but a better play is 6/1* 13/9!

There are several reasons for hitting on the ace-point in the opening. The most common situation is the tempo hit, where your opponent has a lot of threats and you hit so he has to waste half a roll coming in from the bar.

That's not the case here, but this position does illustrate the second most common reason -- the distraction play. These are situations where your opponent has a weak position which he needs to clean up in some way, and hitting prevents the clean up. Typically he might have a lot of blots which he needs to safety, but in this case he has stacks he needs to develop, and by hitting you're preventing him from doing anything about his stacks. Hitting is a way of attacking a stacked position.

Thank you, Bill! All clear.