How should White play 43 here?
This is a position from the world champs where the score has been removed. I just want to remind readers that this is a money position as played in New Zealand i.e., without the Jacoby rule. If it helps, just think of this is the first game in a 25 point match. Gammons are active even without the cube being turned.
It is always good to hit and go ahead in the race, unless you are in a priming situation. Consider 24/21* 7/3:
You go from being behind in the race to being ahead in the race. Although you have kept your 4 prime, your opponent has a lot of double hits here from the bar.
If you are hitting, is 7/3 the best move with the 4? You have duplicated your own 3’s to cover, make your 21 point anchor and play 21/18 escaping.
If you are going to hit the better play is 24/21* 6/2:
This move diversifies your future rolls giving you 5’s and 4’s to cover the blot on your 2 point and 6’s and 3’s to anchor or escape on your opponent’s side of the board.
Although this starts a deeper point in your board, because of the diversification it is the better move.
But this is a prime versus prime game, so should you be hitting? If you do not hit, after this roll you will still be behind in the race which is what you want in a priming battle.
Consider 7/3 6/3:
This move leaves no blots, and makes your opponent’s 6’s and 5’s except for 64 and 54 into very bad rolls. They will be short on time, with an awkward structure.
The big weakness of this move, is that our prime is not a compact prime meaning we have the gap on our 5 point. Having this gap is worse than leaving blots in your outfield.
You also have TMP here. Too many points or TMP means you have no spares and an inflexible, brittle position.
Consider 9/5 8/5:
Now you have a compact 4 prime, with spares so that you have 4 builders for your 3 point and 3 builders for your 2 point.
If your opponent splits to your 3 point, you can fight for the edge of the prime because of your diversified spares.
Any 1 could be used to play 9/8 giving you a 5 prime. After you have a 5 prime, you do not mind splitting your back checkers and letting your opponent attack and close you out, as their board will soon be crashing. When it does you can easily enter and win the game.
This is the correct move.
The take away from this is when you make a move that results in your position having TMP, you need to think very carefully about that move. There are times when it can be right but those are rare occurrences rather than the norm. Also, spares are good and hitting is not always the correct play.