Hockey hash marks are lines on the four faceoff circles across the hockey rink. The hash marks are two feet and two inches long and four feet apart. The marks are red colored, to differentiate them from other lines, like the blue line and the goal line.
During a face off, two players, almost always the centers, face each other in the center of one of the five face off circles. Four of these circles are positioned at either side of the ice and are used for icing calls, or when the goalie holds on to the puck, among other reasons. These are important because they give the attacking team an advantage if they can win the faceoff. The last face off circle is in the middle of the ice and is used to start the game and after any goals.
During all face offs it is up to the two centers to try and win the puck for their team. There are many different formations that the remaining players can be in, as long as they stay behind the hash marks. When you are near the opponents goal you might want to win the face off quickly and pass to a player in open space who can shoot. On defense if you win the face off you may want to dump and chase or move the puck around quickly to get it out of your area.
Where you are taking the face off will affect what you want to do in terms of strategy. You might position three players on one side, for instance, in an attempt to block the goal. Or you might isolate someone with a good slapshot to take a hard shot on goal. This will all change where players go, as long as they're within the hash marks.
Hockey hash marks are only important during face offs. During regular play, the hash marks serve no purpose. If you are just skating around, you can cross them, you can stand on them, you can shoot from them and do whatever you want. During a face off however the hash marks serve an important purpose. Hash marks separate the players during a face off. While the centers fight for the puck in the middle of the circle they must both stay behind hash marks that only their sticks are allowed to cross, until the puck is dropped. Outside of the circle, all of the other players are also confined to their own hash marks. Players from the attacking team have to stay on their half, further away from the goal in which they are trying to score. They are seperated from the other team by hash marks.
Technically there are five face off circles on a hockey rink. One of them is the center circle and it is a little different than the other four. The center circle is used for face offs at the beginning of periods and after a goal. Players stand on either side of the red line while the centers take the face off. The other four circles are positioned on either side of the ice and are used after certain penalties are committed. These circles are smaller and have hash marks to separate the players.
Put simply, hockey hash marks separate players during face offs. These marks keep players from opposing teams on either side of the face off circle. The attacking team has to be away from the goal that they're trying to score on and the defending team has to be on the side that they're defending. The hash marks help to organize players and keep them on their respective sides. Teams come up with formations and other things during faceoffs but they are bound by having to stay on either side of the hash marks.