This is "man-to man" marking and requires a lot of pointless running, and the problem arises when a man is beaten by his opposing number, and now there is no-one to meet the ball carrier as everyone else is marking. These situations are always arising and when a player steps off his man to meet, there is now an easy passing option available to the ball carrier, i.e.: the free man.The trend in modern hockey is to employ a zonal system of defence. This system is generally used when you have the opposition in their own half, and preferably on one of the sides of the field. E.g.: 16 yard hit.

In employing a zonal system, the entire defensive team aligns itself according to where the ball is in relation to the most dangerous pass, which could be available to the opposition. Normally this would be a pass directly into the middle of the field, which allows the opposition to then dictate the play. The zonal system should allow the opposition a square or backwards pass, but once this pass has been made the defence should quickly realign them selves with the new dangerous pass options available to the opposition. Is crucial that all 10 defensive players are away of their roles at all times, as any gap in the "wall" could have disastrous consequences.
If this system is done correctly, the defending team can push forward as a unit with little concern as to the opposition strikers movements behind them, as a ball should not be able to find its way through.

Communication
The biggest key to a successful zonal system is communication, and this starts with the keeper. The players behind call the players in front into the correct lines. The centre back and centre midfield are pivotal roles in this communication system. The players up front are under the obligation to place the ball carrier under immense pressure, thus resulting in an ineffective or unsuccessful pass. If these players up front try to actually win the ball in a tackle, they will more than likely give away a free hit, and the whole process must start again, whereas if the ball carrier is made to pass the ball under pressure, there is a strong likelihood that it will be intercepted by the midfield who are waiting behind.