Final answer:
Allocating a heavy unit to relieve a light unit requires careful planning to avoid exhaustion, maintain leadership, and ensure support between divisions. Forced marches and distances impact the effectiveness of relief and coordination, underlining the importance of strategic logistics in military history.
Step-by-step explanation:
When a heavy unit is relieving a light unit, several factors must be taken into account to ensure the transition does not result in a strategic disadvantage. From the text provided, it's clear that speed and distance are critical concerns. Making forced marches to cover double the usual distance or attempting to cover 100 LI to secure an advantage can lead to exhaustion and vulnerability, potentially resulting in the capture of the unit's leaders by the enemy.
Moreover, if the army is spread out with significant distances between its divisions, coordination becomes a major issue. Should the units be unaware of the appropriate time or place to combine forces, they will not be able to provide support to each other effectively, rendering sections like the left or right wing, van, or rear impotent in terms of mutual assistance. Thus, proper planning, communication, and allocation of resources are essential when one unit is taking position from another, particularly under strenuous conditions or across large distances.
The information suggests that careful allocation is vital, including the distribution of leaders, the pacing of troops to avoid needless casualties or disorganization, and ensuring the resilience and support-capability of the units involved. Understanding these concepts is crucial for successful military strategy and can be directly applied to historical contexts where military logistics played a key role in the outcome of conflicts.