Military service system can be divided into compulsory system and voluntary system. With compulsory system, military service is required following the concept that all citizens of a nation are responsible for the defense of their country. The compulsory system can be further divided into drafting system and militia system.

Draft system :

Based on universal conscription system, every citizen is subject to military service requirement, and the recruited soldiers undergo an education and training to become elite soldiers. The service is for a set duration and soldiers are transferred to reserve units afterwards. The reserve is mobilized during an emergency or wartime.

Militia system :

As in drafting system, militia system is also based on universal conscription system, and the purpose of military training is to cultivate and maintain the military force economically. The officer positions are filled with volunteers. All citizens receive a short term basic military training, and in time of peace, people carry on with their lives. In an emergency, the citizens are summoned for military service in wartime. Volunteer military system is also called a free military system and individuals enlist in the military service at their own will signing a contract with the nation. Professional soldier system, recruiting system and mercenary system belong to this category.

Professional soldier system :

In this category, people are soldiers by profession. People who are willing to serve long term in the military become commissioned and noncommissioned officers, and they receive enough salary to keep a family.

Volunteer military system :

At their will, people sign a contract with the country, and serve in the military by enlisting in a specific forces, positions and branches of the service.

Mercenary system :

Salary and service period is determined by a contract, and mercenary system is an employment system for the purpose of financial enrichment only. Foreigners may enlist in the service, and France’s mercenary system is an example.