Conducting a War
So, your story takes place during a war. Maybe your characters are experiencing war or maybe they're waging war against other characters or groups. Likely, you are not a general or expert in warfare. How do you write a story that is set during a war?
Who's fighting who?
The first, most obvious, step is to know who is fighting whom and why. Wars are between groups of people. They can be a small clan, a massive nation, or even an entire planet or galaxy. Two characters fighting it out are not considered "at war" because they are representing themselves and settling an individual dispute, even if it is a high-stakes dispute.
Why are the parties in your story fighting? There are a lot of different reasons why two groups of people would go to war against each other, but most wars are over resources at their center. Disputes over land and borders, over who gets what crops and for what price, and even religious wars are usually about the resources available and scarcity. So when you're talking about war, you need to know what either side wants. Just like a character, your war parties need to have desires and stakes.
"Resources" can mean just about anything that society needs. Food, fresh water, opportunities for trade, minerals, metals, building materials, and wealth are all examples of resources your war parties can fight over.
What does it take to wage war?
Wars require resources too. It's not just about getting resources but spending resources as well. When nations go to war in the real world, there are opportunities for people to make exorbitant amounts of money and wealth by taking advantage of a wartime economy.
The parties waging war need people to fight their battles. They need to pay those people, arm them, feed and clothe them, and transport them to where they need to be. Where does the government or person in charge get the food, armor, weapons, and transportation? Where do they allocate those scarce resources? Oftentimes in war, those in charge must make sacrifices. Is there a portion of land that the person in charge gives up to protect another portion with their limited resources?
There are unlimited stories hidden in these questions, and a large base of world-building will help to answer these questions in depth. There are many opportunities for tension and rising stakes for your war parties in the event that the opposing side makes acquiring war resources difficult or impossible.
Types of Armies
Your armies tell you a lot about the resources available to your characters and how you can build your story and plot line around the war. So I'll discuss the differences between four types of armies that exist in the real world and throughout history. These are examples; you can change or twist these examples however best suits your story.
The first is a professional army. These guys are paid and trained by the state; being in the army is their entire job. The army can fill a number of different roles other than fighting, but their purpose is to provide martial protection to the people of their nation and carry out martial orders from the government or sovereign entity in charge. Important aspects of a professional army to consider: these soldiers are paid for their work, they are trained by professionals, and oftentimes they follow a hierarchy or chain of command. Most governments provide medical care to their professional armies, but this isn't required. The soldiers can be conscripted or voluntary.
Next up is a mercenary army. This army is also paid for their services, but they are not trained by the state, and they ultimately take their orders from the organization, not the government. The government commissions the mercenary army for their services. The government does not provide most of the resources required to maintain an army. They pay for the army but don't necessarily feed, arm, or clothe them.
A fyrd is a historical term that refers specifically to the Anglo-Saxon armies raised by different Lords and Thegns to protect their lands and shires. These armies consisted of civilians and able-bodied free men from the local settlements and farms gathered by the ealdorman. They were conscripted into the service, and they lacked formal martial training. Also, importantly, their provisions and weapons were provided by the soldiers themselves. Meaning you will see fewer long swords and forged weapons for the purposes of fighting and more axes and improvised weaponry. The purposes of the improvised weaponry are primarily as other tools, such as axes for chopping wood and knives for butchery. Any horses or mules brought along for work or fighting are the property of the lords or farm owners who provided them.
A militia is very similar to a fyrd; this army consists of civilians who are paid or conscripted into service by the government but are not professional soldiers. These militias may sometimes have training from professional soldiers among their ranks, but mostly they are civilians training themselves. The soldiers provide their provisions, weaponry, and armor, meaning that the wealth has to come from the soldiers and their professional jobs and not from their martial services. The militia is a more modern term, but it is marginally different in that most militias we think of today are voluntary and not conscripted.
Battle Strategy
This is where a little research may help you. Battles behave differently depending on different factors. What technology and weaponry is available to your war parties? Are we talking about bladed weapons or guns or lasers? Is your army a professional or mercenary army, or is it more like a fyrd or militia?
When setting up a battle in your story, focus on the differences between the two armies and how that may affect their strategy toward fighting or engaging the enemy. If your fyrd faces a professional army, they may encounter some problems regarding weaponry and armor. Your fyrd will struggle to match a professional army in defending against well-made weapons and professional training. How do they work to compensate for those weaknesses?
When looking at two equally armed and trained armies, a general or battle strategist will look to the terrain to plan a battle. Generally, controlling the high ground helps in battles. If one army has a heavy cavalry presence, your opposing army may want anti-cavalry measures in place. Do they have the space to do so? Urban areas will lend themselves well to guerilla-style and urban warfare tactics. Jungles and forests will look different to hills and plains, and deserts bring unique problems to a battle that a mountainous terrain might not.
What is the battle for? Battles have a purpose; otherwise, there would be no value to the loss of troops. What is worth the risk of losing lives? Does the battle have stakes? Some stakes that might be worth conducting a battle over include taking control of a river pass, allowing naval trade and travel, cutting off control of a trade route to the enemy, or invading an important town or city to process and refine necessary materials.
Ending the War
The war will eventually end if your characters are lucky. But what ends a war? Wars usually end with agreements between the two opposing parties following surrender or extension of peaceful negotiations. Negotiating what each party needs or wants is an art in and of itself. Each party must come to the agreement that waging war further is more expensive and less rewarding than ending violent opposition with concessions made by either side.
Conclusion
Wars and battles are like characters; they have needs, desires, and stakes. Writing your characters in a war or battle will hinge on the needs and stakes of the greater war and story. Important questions to ask are: what are we fighting for? Who are we fighting? And what happens if we don't fight?
–Indy
