Among the most interesting backgammon positions are those I like to call the proto-back games. These are games where the defender has several men back, perhaps behind a prime, perhaps not, and can still go in several different directions, one of which is a full-fledged back game.
Although they don't come up as often as other game types, proto-back games are full of weird and counter-intuitive plays, making them some of the most fascinating positions to study.
Black to play 6-1.
In Position 1, for instance, the right idea is one I've never actually seen anyone play over the board. Black should play 9/3!, slotting his 3-point, and then either 8/7 for better coverage or 14/13 to duplicate aces (either choice gets full credit). Why slot a point when you have good distribution already and your opponent is on the bar? Examining White's upcoming rolls carefully gives the answer, and it's an instructive one.
When White fails to hit, Black has gained noticeably as a result of slotting. This seems obvious when stated, but most players don't really think about it when assessing the position. If Black slots and White misses, Black rolls his prime home much more quickly and wins more gammons.
Black is worse off when White hits, but not by very much. Sometimes the extra checker back helps Black pick up more men as White tries to bring his disjointed position home, resulting in a few more gammon. Black would prefer not to be hit, but he loses only about as much equity when he's hit as he gains when he isn't hit.
Black only gets hit 12 times, not 15. It turns out that 21 and 11 are trap rolls for White. He's supposed to forgo the hit and just make the 23-point instead, aiming to save the gammon in a busted ace-deuce back game. Most players would miss this, making the slot even stronger.
Black gains as much when White misses as he loses when White hits. But White has many more misses than hits, so the slot is a big winning play.
Next time: The Over-Stretched Position