Wall of Force

School force (spell)
Action 1 standard
Range close (25 ft. + 5 ft./2 tiers)
Effect wall whose area is up to one 10-ft. square/level
Duration rounds equal to your cultivation modifier + 1 round/tier

You conjure a wall composed of force energy. The wall barely has any thickness and is invisible, but it blocks physical movement through its space and line of sight for targeting arts and other abilities. The wall itself can be targeted, and it has a DV of 0 and a durability of 2.

Refinements

Reinforced (+1)

Increase the wall's DV by 10 and its durability by 2.

Sudden Wall (+1)

You can cast the art as a reaction, but only in response to an attack or effect in order to block its line of sight.