Silkroads: Spreadsheet Balancing and Application to the Game

In my previous post on spreadsheet balancing, I introduced my process of finding key values – in particular, how quickly resources need to drop in abundance for trading to be profitable – that will shape the first pass of balancing in Silkroads. While previous balancing, specifically regarding the spread of abundance across the map:

… was done by eye, this likely won’t do. With some simple plotting in Microsoft Excel, I’m able to understand how this spread should look to produce profitable, unprofitable, and neutral routes.

Again, here’s the table of calculated Critical Delta Abundance (CDA):

I’ve added rough distance indicators to give a sense of the distances that these values represent. Remember, red cells (larger than 1) are impossible to trade profitably in any situation, on a base-infrastructure route. So, when the player starts the game, the most far-reaching resource routes are those of Silk, Silver, Gold, and Lapis Lazuli. They can be traded, in the best possible scenario, the distance between London and Kiev – roughly the length of Europe. The CDA of Silk is 0.04 delta-abundance per 100km.

I begin by putting these values into the game, along with the other key values I’ve been working with. The standard caravan can carry 100kg of cargo, for example, caravans travel at 500km per year, and it costs 5 coins to travel for a year.

After adding some grid squares to make tweaking-by-eye easier, I create my first drop of abundance: the silk road itself. The distance between Merv and Bactra, I can guess, is about 400km. So I subtract 1.5 abundance between Bactra and Merv. In fact, I subtract a little more, since I want the silk road to be quite a viable, profitable route: silk abundance should drop fast enough for a profitable route to be quite comfortable.

I do the same between Merv and Nishapur, and so on …

Testing this route with a caravan produces some quite astonishing results …

Utilising the maximum carry load, the route is just profitable. This is precisely the desired effect. However, I do feel that the game should be more forgiving, and not expect the player to trade a perfect load each time. So I increase the delta-abundance a little more.

So, here’s the same technique with glass. Again, I start by identifying the production source. The levant was the famous birthplace of glassware in antiquity, with the Belus river – approximately near Tyre – being a notable site. Mesopotamia, too, had reasonable abundance of glassware. These wares were among the most common to be traded West-to-East in return for silk.

The distance between Tyre and Antioch is close to the distance between London and Newcastle: 400km, almost the length of England. I can see on my excel sheet that the critical spread drop-off for glass at this distance is 0.5. In other words, glass needs to drop by 50% abundance each Tyre-to-Antioch distance on the map.

I decide this is too fast, and I’m conservative with my drop-off. A quick playtest will show how this behaves.

Surely enough, the trip isn’t actually profitable. Is this acceptable balancing? Maybe. The player may need to upgrade infrastructure before trading glass becomes an option. Additionally, because buying on both trips can produce far greater profits (e.g. buying gold in Babylon so return to the markets of Tyre), a more complete maps might make the glass trade much more viable.

This is why even this careful tweaking on the first balance pass isn’t enough: playtesting is needed to truly highlight balance oversights.

Running through all eight current trade goods, and adhering roughly to the spreadsheet values, the map looks like this:

It doesn’t seem immediately unbalanced, overall. Most regions have some abundance to offer in trade to other regions. A major exception is the Arabian peninsula. To my knowledge, it wasn’t a production source of Silver, Gold, Lapis Lazuli, Nutmeg, or Cinnamon. I’m sourcing Ebony from Ethiopia, and want to leave the trade potential open for sea-routes across the Red Sea. Arabia needs its own luxury item. And it should be reasonably potent, given that Arabia was a nexus of trade from antiquity onwards.

Luckily, history has just such an example in the incense trade. So, I also add a new trading resource, and populate it across south Arabia.

And with some new non-gizmo UI, that’s the first-pass balance via spreadsheet. Its effectiveness will be of interest in the first round of playtests, which are soon to come. Hopefully, this method will have produced a map lacking in easy exploits, in which the player needs to build up their position by finding subtle profitable routes, before expanding infrastructure to support more lucrative trade.