Position 411

 How should White play 11 here:

You have two types of play with 11 here, first the put Black on the bar play of 5/2*/1:

The idea here is, you are trying to close out Black and win more Gammons. This is a nice theory, but this play wins 4% less games and 3% less Gammons. Also, as you will only have one of Black’s checkers on the bar, you will only win about 3% Gammons.

The problem here is your 63, 62 and 61 play very awkwardly. If you leave a shot and are hit, you will win less games and less Gammons. Other rolls like 54 may make your 2 point, but your 4 point will still be open and Black could enter and escape, then get lucky and win the race.

The best play is to just make a 6 prime with 7/4 5/4:

Now you can use any awkward 6 to hit 8/2* and still keep your 6 prime. You do not care if your opponent hits you from the bar because they will use up a lot of timing, particularly if you stay on the bar. Then their board will collapse and you will frequently get more shots at new blots.

This is the correct play.