Ancient Indians had evolved a modern society and had advanced thoughts about the need for army and the weapons of war. The Janapada concept was expanded to Mahajanapada, which essentially meant that the King conquered neighbouring land to enlarge his Kingdom. With it came the idea of Bharatavarsh. Regular armies were created and rules of war including warrior codes were written. The warrior was respected and given a high place in society.
Our ancestors used two terms - "Regular Army" and "Proper Army". The word Regular means a permanent army composed of soldiers who are dedicated and devoted to the task of protecting the nation and its people. A Proper army means an efficient fighting machine. An army, which is well trained and always ready for battle, can be called a Proper army.
All armies of the world are required to fight in all types of terrain and are accordingly equipped. India has vast and diverse terrain features ranging from mountains, deserts, plains and forests. The army had to be mobile to cover great distances and therefore chariots and cavalry formed the core strength along with infantry. The ancient armies were made of the Chariots, Elephants, Horses and Infantry. Collectively it was called Chaturangabala.
The four fold Chaturangabala was the traditional force. A King had a number of chariots, horses and elephants. All these required a minister or department of state to look after and also required money to feed the animals, pay the soldiers and provide accommodation for the soldiers and their handlers. Therefore, to control and administer large armies new organisations were created such as a ministry called Mantra, the force of counsel and Kosha, the power of the treasury.
Thus it became a six fold force. As societies progressed the organization of the army was further strengthened, due to its deployment in different situations of war. It became an eight fold force to include, cara or spies, commissariat and transport, navy or Admiralty and Desika or elders and advisors.
Chariots: In Vedic times, the chariot was considered the most important to fight a war. It could maneuver through the fighting forces thus suddenly occupying positions of advantage, break through ranks and threaten enemy from the flank or the rear. Each chariot had a charioteer and the warrior. A flag decorated it with an image called dhvaja and an umbrella. The use of the chariots declined by 650 A.D. and no mention of its use is made in any historical texts in later years.
Elephants: The next important force of war was the elephant. In peacetime it was used as a vehicle to carry men and material. In war it became a combatant. Mention of elephants in battle is found in Rig Veda. The Arthasastra describes in great detail the role and tasks of a special officer to take care of the elephant division. It also mentions the area required to house one elephant in designated areas called elephant forest and its food and training requirements. The importance of elephants as a powerful means for battle can be seen from Gajasiksa or hastisastra, was a special science of elephants and formed an important part of military studies.
Cavalry: The third division of the army, was the cavalry. Again, in Arthasastra, detailed descriptions are given of cavalry division. There was a Superintendent called as vadyaksa who was responsible to maintain the horses. A cavalry unit was the fastest moving force of an army and it could be employed to gain surprise and it played an important role in battles.
Infantry: Infantry was the next important division of the army. Infantry gave the army its numbers, which became the factor for many victories. The Arthasastra talks of the Infantry as a separate department of the army, under the charge of a special officer of the state. All infantry soldiers carried a sword or a dagger and a shield. In addition they were equipped with a bow and arrow and some with firearms or javelins (long spears).
Commissariat: The chaturanga or the four-fold division of the army was initial organisation of the army which was later improved to an eight fold division which included the Commissariat and the Admiralty. The Commissariat can be traced to the Mahabharata armies. It was basically an organization responsible to provide logistic support. That is to say, armies marched to the battlefront and the support in the form of extra weapons, rations and camping stores followed the marching army. This also included medical support and repair items for broken chariots, etc.
The Admiralty: The use of ships and boats were known to the vedic people but the idea of creating a separate department to coordinate and control the war ships was done by Chanakya. We find reference of ships in the Rig Veda, Dharmasastra and the Puranas. Tamils and people of the East coast of India, used ships as early as the vedic period, extensively for trade and conquest of neighbouring lands. There were three classifications of war ships. The first was ships with compartments to carry soldiers, the second carried the King, treasures, animals, etc., and the third was a ship used for long distance sailing and seafights.