Which correction includes the direction for an artillery mission?

The term "OT Direction" refers to the "on-target" direction, which is the specific directive provided for an artillery mission. This direction is crucial as it indicates how the rounds should be aimed in relation to the target, ensuring that they land accurately at the intended location. When calling in artillery, the use of OT Direction helps the fire support team to establish a clear understanding of the target's position in relation to the observer's location.

Other options mentioned have distinct definitions that serve different purposes in the firing process. For instance, "Deviation" typically refers to adjustments made to account for errors in direction or fire, while "Target Description" provides details about the target itself—including location, type, and other critical characteristics. "Splash" is a term used to communicate the imminent impact of artillery rounds but does not provide directional information. Therefore, the correct answer focuses specifically on the aspect of directional guidance needed for the execution of an artillery mission.