Technically the term "resource" can refer to almost anything. In this case it will refer to things such as Food, Wood, Iron, Stone, Materials and suchlike.

Resources, you never have enough of them

Resources are what allow a nation to do things, if you have enough wood then you can make ships. If you have enough Iron you can create weapons. If you have enough stone you can make castles and if you are rich enough, you can simply buy anything from that list.

Fun though it is to keep detailed records of every single resources, World of Arl needs you only record the amount of two resources; Food and Materials. Food cannot be stored for long and any you had at the end of one turn does not carry over to the next. Materials on the other hand can be stored up. There are in addition three other elements called Supplies, they are Wood, Stone and Iron but we'll come on to them later.

City

The World of Arl map is split into landmass, each city on the landmass produces a certain amount of food, a certain amount of materials and can have access to a supply such as wood. For those that are like me and can't remember how to read a grid reference, X is a-cross and the alphabet goes vwXYz. So X is across and goes before Y.

Food

Food is used to feed your people, you can't have too much food but if you have lots of it then your people will be happier and your troops have more morale, not enough of it and they will possibly riot, move to another country or even just starve to death. Food can be transported so if you do not have enough food, it is possible to buy, steal or beg food from another country. Additionally, if you do not have food then you are unable to train new warriors as they are all too busy farming for food.

Each city produces food for up to 75,000 people. If you have extra food then you can give it to other people or use it to make your people happier. Having twice as much food as you need means your people's morale is twice what it would be normally, three times as much food means three times the morale. Having too little food will cause population growth to slow and stop. Having only 50% of the food needed will stop population growth, 75% of what you need will halve it. Anywhere below 50% and people will start to die or try to migrate.

A city normally produces 1.5 food for every 1 person living there, this can be increased by researching the farming technology. 1 person normally eats 1 food a turn.

Materials

Materials are created based on the number of people living in the province, lots of people means lots of money. Materials can also be transported, and anything being transported can be stolen. Each territory produces 1 material for every 1,000 people living there. Cities or villages too small to appear on the map are also too small to provide resources for your nation.

Supplies

Aside from Food and Materials, you also have Supplies. With a supply you either have it at a location or you do not, you never have a limited amount of it. Supplies make it cheaper and easier to do things, without Iron your metal weapons and armour are 4 times as expensive. Without Wood your ships take four times as long to build and without stone you both cannot build walls and your normal buildings take twice as long to build.

Supplies are thus useful things to have. Supplies are map specific, stone comes from mountains, Iron from hills and Wood from forests. Supplies can be transported over land and between shipyards. Such supply routes can also be attacked and stopped.

Economic warfare

As everything you do costs a certain amount of materials, if you can deprive an enemy of their materials (normally by stealing it) then they will be unable to buy anything. However, materials are not normally left lying around and is thus not very easy to steal. Much easier is to prevent them from getting the supplies that they require.

Assume if you will that the "Aggregate" control an iron mine and are happy to trade with "Ranil". Ranil don't have any supplies of iron for themselves and thus rely on the Aggregate to supply them with iron. If you wanted to strike at Ranil, stopping the supply trains from the Aggregate to Ranil will remove Ranil's supply of Iron and they will be forced to pay through the nose for Iron weapons.

Being a supplier

Supplies can be shared with anybody that has a connection to your supply location, be it over land, sea or a combination of the two.