Hockey tactics are fascinating. Trying to control the flow of a game as fast as NHL hockey means strategy in constant motion. Some players make a career out of positioning while others play like a wild horse but have the talent to get away with it. I'm interested in the synergy of the two.
It's hard to exaggerate the susceptibility of humans to illusion given the limitations of our anatomy. This is how the neutral zone trap works. It also happens to be how butterfly goaltending works, but I digress. The above diagram of polar coordinates looks like the diagram for the trap (it does to me anyway). Shepherding the puck carrier using a simple pincer attack with a second level of defensive pressure results in the loss of time and space, the inability to do anything attractive with the puck, and finally, panic.
The panic sets in as the naive puck carrier realizes that the boards he's being forced into aren't going anywhere and because of a phenomenon known as angular velocity. Angular velocity in ice hockey can become linear velocity very, very fast. The difference is this: when watching an approaching train from afar, it appears to be moving very slowly (angular). As it's passing you (linear), you realize that it's moving and has always been moving very fast.
The defending players are tasked with placing the attacking player in statistically poor portions of the ice. This means eliminating passing lanes and skating lanes while in motion. It means knowledge of using the blue line to keep the neutral zone as small-looking as possible. The trapping players actually enjoy a good deal of flexibility when the team uses the speed neutralization of blue line. It's brilliant to watch unless it's your team falling into the trap.
I'm going to put together a post to investigate offense, specifically optics and angles. Until then, happy media day.