A, B, C, and D form the diamond. A marks 2 straight up. A cannot allow a middle pass in front of D. ^ is the deep safety
We are giving up the wings, inviting the offense to pass the disc within the red triangles (I lost 2 lines and can't get them back - imagine two red, right triangles).
1 advances
The offense passes to the open space on the left
B moves up to mark 1. We will always force line, so B's mark forces 1 to throw the disc to 1's left
A moves up to give light pressure to any possible dump passes
C and D shift over to further strengthen the left side. The diamond is somewhat reformed, shifted to the left.
The playside $ cheats up. He will play very aggressively to guard the line. He over plays the short pass and gives up a deeper pass
Because the playside $ is playing up, the deep safety rotates towards the disc to guard against a deep pass. The deep safety should prey upon anything that gets lobbed past the playside $
The backside $ also cheats over, He can see the whole field and he must guard the most dangerous threat without giving up a deep pass. He and the deep safety are in deep halves - they split the deepest part of the field and must not allow any passes to travel behind them
From here, our entire defense is positioned well to make a play, and the offense is left with few choices, such as testing the deep safety and attempting a difficult cross-field pass. D has a hard job. D doesn't want to allow a pass inside the diamond, but D also cannot allow a pass behind him and in front of the safeties. Consequently, D needs to be a smart, athletic player with good instincts. A is pressuring a dump pass, but A's first responsibility is to help D by guarding the interior of the diamond. B can help guard the diamond with a good mark. C is roaming free, looking to eat up any dangerous cross-field passes
If we do our jobs right, the only safe play for the offense is a dump, which A will pressure to make it difficult, but will ultimately give up to protect the interior of the diamond.
A moves up to mark straight up and the diamond returns to its original position. If A was guarding a receiver in the diamond's interior, D must pick up that man as A leaves to mark the handler.
The safeties also rotate back, picking up the receivers in their area. We are back where we started and will once again, give up the wings.
Sometimes we will get beat inside our diamond
When that happens, we all shift back, A picks up a new mark
Alternatively . . .
If . . .
We get beat in the interior a little deeper . . .
D will pick up the mark
We hustle back, the safeties trying to cover for the gap D has left
A takes over D's spot, and we're back in our diamond
If they get within striking distance of the goal line
We immediately switch to man
Remember, offense has the advantage in ultimate frisbee - the defense cannot hold every time. Our goal on defense is to make scoring hard for the offense and try to force them into making mistakes. I still think our base defense should be man to man, but a zone concept like this one is a good change of pace that will hopefully confuse the offense and keep our defenders from tiring out.
Meh.