Neutrality

Neutrality is non-participation, whether direct or indirect, in war. It exists only during war and is governed by international law. A state that doesn't participate in armed conflict but doesn't behave like a neutral (non-belligerency) isn't considered as a neutral. Semi-neutrality is not recognized in international law.

Neutrality ends when the hostilities cease or when the neutral country itself enters the war.

Neutralization is international law refers to a state becoming neutral permanently (like Switzerland.) Neutralization is the result of a treaty where the neutrality and independence of a state is guaranteed by other states, usually the superpowers, under the condition that the neutralized state will not participate in military conflicts except in self-defense.

Rights and Duties of Neutral States

1.) Not to take part in armed conflict and giving assistance to any of the belligerents by either sending troops, granting official loans or carrying contraband.

2.) To prevent its territory and other resources to be used in the conduct of hostilities (ex. allowing use of its airspace.)

3.) Agree to restrictions and limitations imposed by the belligerents such as blockades and visit and search of neutral vessels (and sometimes subjection to the authority of prize courts.)

Contraband

In international law, this refers to goods that come from a neutral source but can be seized because of their usefulness in war or are destined for enemy ports. Contraband can be absolute (like weapons,) conditional (like food and clothing, which can be used by anybody) or free list (like medicines.) Free list cargo is exempt from contraband on humanitarian grounds. Goods intended for civilian use which will end up in enemy hands can be seized on the way (doctrine of ultimate consumption.) Innocent goods shipped together with contraband may also be seized (doctrine of infection.) Goods unloaded in an intermediate port or loaded onto another vessel may also be seized due to the doctrine of ultimate consumption (doctrine of continuous voyage/transport.)

Blockade

A blockade is an operation where vessels and aircraft of a belligerent or neutral state are prevented from entering or leaving the ports of another belligerent. The purpose of a blockade is to shut an enemy state off from international trade and communication. Pacific blockades refer to the vessels of states under blockade, not to other states. The requisites of a blockade are the following:

1.) Binding: duly communicated to neutral states

2.) Effective: maintained by enough forces to make entry and exit of the blockaded area dangerous

3.) Established by the belligerent government's competent authority

4.) Limited only to enemy territory

5.) Applied without bias to all states

A neutral vessel captured for breaching a blockade is presumed to know about the blockade. Belligerent forces have the right to board and search neutral vessels to find out if they are in any way connected to the hostilities. Vessels captured for engaging in hostile activities aren't automatically confiscated. They're brought before a prize court, which is a court established by the belligerent under its own laws, or under international law  (if there is no local legislation) in its territory or in that of its allies.