Morten Wang (O) vs Vemund Snartland (X) Vemund (X) leads 6-4 in a 7-point match (post Crawford). +24-23-22-21-20-19-+---+18-17-16-15-14-13-+ +---+ | X X X X X X | | X | | | | X X X X X X | | | | 2 | | X | | | | | | | | | +---+ | | | | | | | | | | | | | | | | | | | | | O | | O | | O O O | | O O O | | O O X O O | | O O O | +-1--2--3--4--5--6-+---+-7--8--9-10-11-12-+ Pip-count: O: 80, X: 78 O rolled 6-1.Over the board I considered to candiate moves: 9/3, 5/4* and 9/3, 9/8. There is also another move I should have considered, 7/1, 3/2. The one I missed was found by Jellyfish to be the 2nd best move, but I never gave it any thought.
When I tried to find which move I wished to make I started counting rolls. First I wanted to know how many of X's rolls would hit after I hit him. Any 4 will hit, as well as double 2, so the total is 12 rolls. If I choose to roll the prime forwards X will escape with any 5 or 6, which is a total of 20 rolls. So I end up with better odds of X not hitting me than om him escaping after I roll forwards.
But I wanted to play safely. Gammons don't count for my opponent, him being only 1 point away from winning, but if he hits the game is probably a clear loss. If I roll forwards he has 16 rolls that won't get him over the prime, and I have good chances of hitting and then to close him out. If he gets over he will probably lead in the race, and his good distribution in the inner board should make the bearoff an easy task. Of course, it's then all up to the dice to decide who wins.
I never considered playing 7/1, 3/2 at the table, mainly because I have a habit of rolling my prime forwards on occasions like this. I've seldom rolled 6-1s and therefore had an easier task. During a few games I've played after this occured I have tried to do the waiting move, not doing anything with the prime. It gives your opponent a tougher task of getting past it, and has proved to give me an easier win. The win is not necessarily very easy, but with a bit of thinking it's not incredibly difficult to bring your men in and off without too much trouble.
So now I know that I'll hit here, even though my opponent has a closed board. It wasn't easy to find the solution to this problem over the board, but Jellyfish and its rollouts gave me a trustable answer. The other possible moves are not moves that clearly loses the match, but they are quite clearly not as good as hitting. I have written down the rollot results from Jellyfish below, so you can see and decide for yourself.
Move: | 9/3, 9/8 | 9/3, 5/4* | 7/1, 3/2 |
---------|----------------|----------------|----------------|
Cubeless | 54.8 1.2 0.0 | 43.1 17.6 0.5 | 50.5 3.9 0.0 |
equity | 45.2 0.8 0.0 | 56.9 1.9 0.0 | 49.5 0.5 0.0 |
| 0.100 | 0.023 | 0.046 |
| 0.028 | 0.035 | 0.030 |
---------|----------------|----------------|----------------|
Cube | 56.5 0.4 0.0 | 33.5 14.9 0.5 | 48.8 2.6 0.0 |
centered | 43.5 0.0 0.0 | 66.5 0.1 0.0 | 51.2 0.0 0.0 |
| 0.133 | -0.177 | 0.003 |
| 0.028 | 0.033 | 0.029 |
---------|----------------|----------------|----------------|
X owns | 63.0 0.5 0.0 | 45.3 15.4 0.5 | 57.7 2.6 0.0 |
cube | 37.0 0.0 0.0 | 54.7 1.9 0.0 | 42.3 0.5 0.0 |
| 0.258 | 0.046 | 0.176 |
| 0.027 | 0.035 | 0.029 |
---------|----------------|----------------|----------------|
O owns | 48.4 0.9 0.0 | 32.0 17.0 0.5 | 41.9 3.8 0.0 |
cube | 51.6 0.0 0.0 | 68.0 0.1 0.0 | 58.1 0.0 0.0 |
| -0.023 | -0.185 | -0.124 |
| 0.028 | 0.034 | 0.029 |
---------+----------------+----------------+----------------+
The numbers are from top left in each table cell:
X's win percentage, X's gammon percentage, X's backgammon percentage.
O's win percentage, O's gammon percentage, O's backgammon percentage.
X's equity.
Standard deviation.
All rollouts were done with Jellyfish 2.02, level 5, 1296 games, played to the end (full rollout). They also had the same seed (6440).