Related Rule
Practice Relating to Rule 14. Proportionality in Attack
Guinea’s Soldier’s Manual (2010), under the heading “Principles of law of war”, states:
The law of [w]ar rests on three fundamental principles:
3. Principle of proportionality
Principle of proportionality requires to complete one’s mission without causing unnecessary damage. 
Guinea, Soldier’s Manual, Ministry of National Defence, 2010, p. 2.