Step 1

The concept behind establishing a force is to reduce the area of the field that any individual player has to cover. Without a force, B1 can easily throw the disc to any of the receivers, B2, B3 and B4.

Step 2

Example

Step 3

(reset) The defender on the mark (R1) is going to force home (or forehand) by standing on the opposite side and blocking the thrower from using their backhand.

Step 4

In this case, it's much easier for the thrower (B1) to throw to receiver B4 on the open or live side, than it is for them to throw to B2 on the break side.

Step 5

(reset) Lets look at what the other defenders (R2, R3, R4) are doing. They are going to mark up on forced side (home in this case). By doing so, they are reducing the available space for the thrower to complete a pass to.

Step 6

Receiver B4 has the best chance of getting the disc because defender R1 is giving space on the open side. Receiver B3 will be a much riskier option, you can see that defender R3 is right there able to intercept the disc. Receiver B2 is only an option if the thrower can "break" the mark and actually throw a backhand.

Step 7

(reset) A well executed force is especially effective against a vertical stack offense

Step 8

This is because as cuts are made out of the stack, if they are made to the open side, the defenders already have an advantageous position

Step 9

defender R4 is able to easily intercept the disc