424 or 432
Coming from the land where they call football, football and most of the males and it must be said some of the females know what the offside rule is; the game of American football (not to be confused with soccer) or as it is known within the US Gridiron is a game of physical strategy, which is played with two major influences, offence and defence.

Similarities can be drawn to the backgammon offence and defence strategy, in that both games are played tactically.

In American football play is dictated by the quarter back, it is his responsibility to enact out the coaches instructions and shout them out to his fellow players.

Backgammon doesn't quite have the same luxury, but it does have a number combination which could be introduced called 432..or Michael's Rule.

Take the following scenario. It is near to the end, your opponent whom we shall call Red has started to bear off his pieces until by a unfortunate bit of luck WHITE (you) managed to hit one of Red's checkers. Shortly after that WHITE has ended up with a closed board with a perfect distribution of his spare checkers and RED is trapped on the bar. Now from a winning position Red becomes more anxious. But should he be?

Is Red too far away from the victory or can he still be said to be the big favorite?
Read this next piece of text and will and up having an easy tool for assessing these kind of positions. This is "Michael's 432 Rule" with Red's probability of winning 30%.
In defining Michael's 432 A quick rule of thumb is easy and this is it:
When "the player with one man on the bar" has 4 men left on his ace point, the probability of "the player with the closed board" winning the game is between 30% and 20%. Notice the 4-3-2 sequences of numbers, hence the name of the rule.

The positioning of the spare checkers of "The Player with the closed board" defines whether it has to be 30% of 20%. If the distribution is perfect with a spare on the 4, 5 and 6-point then the high value, 30%, should be used. If the spares all are situated on the ace point the 20% should be used.

Looking at the position above, WHITE has an excellent distribution, so using the rule will give WHITE a 30% chance of winning. However, in the current position RED is still a big favorite though.
But what if RED had more than 4 checkers on the ace point?
Easy! Because the rule is valid from having 4 to 9 men on the ace point.
This means that with RED having 9 men on the ace point, WHITE will be between 70% and 80% favourite as shown below.
White's probability of winning is 80%
An example of a bad distribution of spare checkers is shown below.
White's probability of winning is now 70%
A thing to remember is that below 4 men and above 9 men on the ace point, the rule is not accurate enough to be used.
So next time you find yourself on the bar looking at a closed board you will always know the probability of winning the match.
Of course you would also find yourself at the other side of the table while closing out the opponent. Michael's 432 rule applies for both sides.

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