Which round should you use to begin the adjustment of a Final Protective Fire after the first volley?

Beginning the adjustment of a Final Protective Fire (FPF) after the first volley is critical to ensuring that the indirect fire supports the defensive line effectively. The choice of which round to use in this adjustment process is determined by its impact location relative to the FPF line.

Selecting the flank piece impacting closest to the FPF line is essential because it allows for quick correction and better alignment of subsequent fire on the target area. This choice ensures that the fire support is concentrated where it is most needed to discourage or stop enemy advances.

Using this approach allows for efficient adjustment of fire, as it provides an immediate visual reference for the adjustment process. The close impact to the FPF line indicates that the projectile has landed in a position that can be scrutinized for effectiveness, allowing for accurate refinements in subsequent volleys.

Other options, while they might seem valid in different contexts, do not prioritize the proximity of the impact to the target area as effectively. Thus, using the flank piece ensures that the subsequent artillery rounds can be adjusted precisely to maintain effective support in the face of an enemy threat.