The most complex types of game are those where both players have many men in their opponent's home board. They normally result from an opening where hit follows hit and no-one has had time to make points. Today's position is taken from a game between Paul Magriel and Mike Svobodny, two of the game's best players. Black has a 6,5 to play.

Let's try to establish some general guidelines. First it is important to keep all your men in play. Making points behind your opponent is not a good idea as those men cannot be used to build a prime in front of him. If possible you should try to make an advanced anchor, to stop your opponent priming you Play a back game only as a last resort. With many men back it is normal to keep at least two points in your opponent's board. In this type of position one of the players will end up with a back game - make sure it isn't you! Finally, look out for a chance to create bad numbers for your opponent, particularly doubles. An ill-timed set of doubles can ruin a promising back game.

In this position Black could play 24/13 but that looks too loose and doesn't make progress. He could play 24/18, 23/18 but that leaves four blots facing an attack and a three point board - again too risky. The choice seems to be between 11/5, 13/8 and 13/7, 11/6. Normally a play that makes the 5-point will win over one that makes the bar, but not here. kaing the bar makes best use of the men, it duplicates White's ones (they both hit and make his 5-point) and it makes some 3s and 4s awkward for White. When the position was shown to a panel of experts four out of six chose to make the 5-point. The two silicon experts, Jellyfish and TD-Gammon both got it right. Magriel, it should be noted, found the right play over the board.