Wednesday, February 20, 2013

The Golden Pair and ACKS Trade

I went back through and read the ACKS world generation rules today, both because I'm kind of thinking about converting the Wilderlands to ACKS, and because I've been thinking about writing some code to handle the generation of settlement trade numbers.  I still haven't figured out a good input format (since we probably want to take a list of settlements, their terrains and ages, and some encoding of their relative distances and connections with other settlements), but I did notice something very interesting in the generation rules which addresses an age-old complaint about Traveller economics.

In Traveller, from Classic to present iterations (with the notable exclusion of Free Trader and a few other editions I think?), there is a phenomenon known as the Golden Pair.  The Golden Pair is a pair of worlds in close proximity which have inverse market modifiers on several goods, such that you can buy A low on the first planet, jump once, sell A high on the second planet, buy B low on the second planet, jump once, sell B high on the first planet, and wash, rinse, repeat.  They're called a Golden Pair because they're a pair of worlds that you can exploit to coat everything you own in gold.  They don't make any sense in a setting where there are ostensibly megacorporations with bulk freighters moving these cargos in much larger quantities, which should tend to equalize prices across the two planets.

ACKS, interestingly enough, has taken measures to prevent Golden Pair situations from arising.  This, I believe, is the purpose of the Trade Route rules on page 233, which indicate that nearby settlements with a road or river connection have their demand modifiers shifted towards each other by 2 (where 10% * demand modifier is applied as an increase to prices).  The radius of 'nearby' depends on the size of the markets, but is minimally 24 miles for a pair of class VI markets connected by roads and just goes up from there (which seems reasonable; that's a day or two's journey by road).  By comparison, a pair of class I markets could be connected at up to 480 miles by water, which is a very sizable distance.  The essential takeaway from these is that if you don't want to have a damper put on your profit by competition / arbitrage forces, you need to be trading between either fairly distant pairs of small settlements, or you need to be hauling your goods between settlements which are isolated from each other by lack of roads or coastline.  In the first case, your profit is limited by the sizes of the markets involved, since market size directly affected number of merchants available and the amount of cargo they're interested in selling.  In the second, you're trading risk for potential reward, since you can get larger demand differentials on larger markets in closer proximity, but you're having to journey through trackless wilderness to get the goods there.  I love a good strategic risk/reward tradeoff...

Unfortunately, the simplified market rules we were using did not generate this tradeoff.  Under the simplified rules, trade along an established route tended to be more reliable and in expectation more profitable than trade off-route.  This made it possible to trade along routes at greater profits than originally intended, I believe (my mistake, did not take the land value modifiers into account correctly.  Credit for correction to Thomas Weigel).  Reliable, maximally profitable, and safe made route trading the preferred strategy of our venturer, whereas normally it would be something quite possible avoided as "not particularly profitable."

This got me to thinking, though, about whether there was a mechanism by which a merchant could bring route trading's profitability back up to that of off-route trading.  I'm fairly sure this is the intent of the monopoly rules, since a character with a monopoly on a good at both ends of a route can effectively create the extra 20% differential that would exist if there were no route.  There's some potential weirdness with 'convincing merchants to sell you goods'; do all caravans carry large volumes of all cargos equally, so that they can be convinced to sell them?  I guess I'm willing to chalk the whole reaction roll to convince merchants to sell you something up to "only some fraction of them have it, and the rest honestly don't."  Hard to see how charisma enters into that, or why you'd want to sell to a monopoly rather than holding onto your goods and transporting them further, but hey, this is the dark ages and not everything has to make perfect sense.  In any case, it got me thinking that a monopoly on a low-value good in a particular town or other small domain might be a nice mid-level reward to kick PCs into trade (and the wilderness adventuring that goes along with it) for service to a local minor noble, and it might also be a cool way to let the venturer maintain relevance into domain play (ie, the fighter grants the venturer monopolies within his domains on all goods.  Centralized, state-managed economy ensues, at massive profit to the kleptocrats party).

Anyway, I'd like to try the full demand modifier system next time I run ACKS, so I guess I'd better get cracking on that script...  ideally with a feature that lets you save the base (rolled+terrain) demand modifiers so that when the PCs build roads connecting settlements or upgrade a settlement in market class, it's possible to efficiently recalculate the demand modifiers for all other settlements Speaking of which - hilariously, if the party had finished the road between Ironbridge and Opportunity, the full system would tell us that the potential for profit along that route would have gone down, as other merchants started traveling it and equalizing prices.  Their urban revenue would not have risen as a result of increased merchant presence in their city, either.  Perverse incentives much?  I guess the main benefit they would have derived would be increase troop mobility, had they eventually chosen to annex Ironbridge by force...


  1. I found, when I was generating trade routes for my setting, that it ended up being too flat, with not much to differentiate which towns demand what. I'm interested in how this turns out for you.

    1. The tests I have run so far look... OK I think? Rolled a class II market with a -5 modifier for liquor, which propagated out to -3 for the next market up the river, then -1 beyond that.