The TBG-1 trade system is only half right, it uses supply and demand to
modify prices rather than fixing them as completely broken games do, but
still has fixed basic prices for each type of good. Rather than try to
mend the point above by adjusting those basic prices, they should be left
to supply and demand as well.
So, reduce number of trade goods per region to 16 and give each a factory as in TBG-1, but allocate another 16 factories randomly. Have the factory price rise when players buy, and fall over time, so the goods which have multiple factories become the cheap ones, without anyone needing to make up the magic numbers correctly.
At the other end, have each colony buy all the local good types. Buying one reduces the price of it by $15 and raises the price of all other goods at that colony by $1 each. Remove the connection between prices at different colonies as it was daft.
The only remaining magic number is the minimum factory price and the initial colonial price, with the difference defining the average profit per item if players traded randomly.
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The limitation of demanding one item isn't suitable for established players who aren't likely to transfer all their assets to a second position, so relax it for them by making the demand into an officer action. Like trade, it's not tied to a particular officer type so anyone can be a diplomat. Powerful players can then transfer as many items as they can spare officer actions (and demands can include money and status, as well as cargo and modules).
The more interesting points come out of thinking what to do with the diplomacy skill built up by demanding, and the answers are about swindling (in the Merchant of Venus sense) and counter-swindling.
Swindling can be used two ways:
As an action like demand-gift, it has a chance of working even if the other player refuses the demand, you get the item and there's no combat even if the enemy chose not to hand over anything. Think of it as an ensign reporting to the captain that we refused to give up the warp drive and the other guys took it away for cleaning at no charge.
As an action like refuse-gift (which otherwise remains free, not an officer action), it has a chance to avoid giving up the gift and not be attacked, even if the enemy chose attack-if-defied. The ensign reports that we got the new cloaking device and it'll be delivered as soon as they find can it.
As a counter-swindle, it means putting a streetwise officer on defence against any form of enemy swindle attack. The only other defence is unconditional real combat, which avoids any diplomatic phase.
What this gets us is a different dimension of combat, independent of massed weaponry, as even the smallest ship may contain Harry Mudd (or Kirk for that matter), able to walk off with your cargo and leave you pleased with the deal.
This breaks the pattern where powerful ships often have meetings with nothing to fear. Since they can't see the enemy diplomatic skills, every encounter offers the anticipation of being "attacked", so getting new results is always fun.
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The free sample idea doesn't fit a natural trading model of rare goods being the most expensive, since it makes a previously non-existent good both the rarest and the cheapest, needing a very sharp discontinuity in the price movement. Instead just have prices for new goods start near the high end. There's big money in being the first to reach a colony with a diverse cargo of goods they never saw before.
Smoother to start with colonies not buying anything and let players build the markets by bringing in goods that start near the high end of pricing. This goes with the bold step of letting go of fixed average pricing, which was the basis of the three schemes covered so far.
Instead allow colonies to vary in absolute wealth terms, relating the strength of a colony's economy to its complexity, in terms of how many types of good it imports (see Mr Smith on The Wealth of Planets). In practice this is simply implemented by having the price of every good rise a little every turn, and rise again when one is bought. The one bought drops by a constant amount, not related to anything else. Tidy away unavailable goods by removing the demand when the price gets too high (somewhat higher than the starting price for new goods). This all gives higher prices generally in complex economies and on difficult trade routes.
Pillage fits into the model by making the loot from raiding a colony relate to the total prices it offers for all the goods it wants, and having these prices drop because of the raid draining resources from the economy. Raiders and traders may be in conflict over the sheep.
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This is the (later) Olympia model for opium trade, but with a few tweaks it can fit the trading model described in earlier mail today.
Assume that contraband goods are special not only in an arbitrary alien legal system, but because they're actually bad for the economy (drugs reduce available workforce, weapons reduce capital goods as well by blowing them up, dodgy software soaks up many sorts of resources). So whereas selling a normal item to a colony increases the prices they offer for everything else (by increasing their general productivity and wealth), selling them contraband _decreases_ the prices they offer for anything else.
The amount of decrease relates to the price of the contraband, with the decrease increasing as the price decreases (pause for parsing), except no prices fall below zero. Ie the more non-productive stuff the colony has, the less it can afford to pay for anything (even other non-productive stuff).
The trick for seducing players into trading contraband is that the demand for it is also unusual, in being derived partly from the strength of the rest of the economy: the rich can better afford pointless or dangerous toys. So take the price reductions on all the other goods and pay them to the contraband seller as a bonus.
The pattern then is that when starting to sell contraband to an already successful colony, the prices are only as good as for other new goods. But as the basic contraband price falls it sucks in bigger bonuses from all the other prices, which fall faster and faster. Various things could happen next:
1) The prices of everything get so low that there's no point trading (or even pillaging) any goods there for a while.
2) Anti-contraband trade pushes the contraband prices up fast enough to eliminate demand, or at least keep it from having much bad effect on other prices. Since this makes it more profitable for the contraband dealers, it seems unlikely to work unless they are forcefully discouraged from selling.
3) Some sort of equilibrium emerges with prices generally low but a few high enough for worthwhile trading, and only occasional contraband sales viable.
The pattern for weak economies is quite different as the bonuses for a very few items are small. A few sales of contraband are profitable as for any other new item, but once they drive the price down there's little support from bonuses, since the small and impoverished population can't afford civil wars or bloated operating systems.
So the pushers and arms dealers need to concentrate on big urban centres, and the honest merchants/pillagers need to keep them as far away as possible.
The political implications fit better into another thread, so I'll leave those for now.
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So this is a good time to say I've taken a dislike to everything in the current trade system?
It looked good in discussion, with supply and demand pricing and open-ended market creation/destruction, but in practice it has several severe flaws:
1) It's much too bland: being able to sell anything anywhere gives wide but meaningless choice. It's a system that invites automatic algorithmic solutions rather than judgement, planning or outwitting opponents.
2) It follows the TBG-1 model of trading mainly with NPCs, rather than the much richer Between model of trading mainly with other players, using NPCs only as the ultimate source and destination of goods.
3) It retains some ugly mechanical features of TBG-1 trading, with awkwardness in the case where more than one player sells the same good to the same colony at the same time, and encouraging players to carry long-term inventories in the knowledge that they'll come in useful later (a system should always reward the lion over the elephant).
So, new system based on trains, using ships as the locomotives and cargo as the trucks, with marshalling yards left to the players to organise.
Implement cargo as special modules (ie each is a unique item rather than a generic unit of goods) with several attributes including destination, prices at source and destination, rate of decay of destination price, and perhaps mass. These cargoes appear with random details, either simply at homeworlds or with some more complex chrome (eg fruit-growing locations produce fast-decay items). Destinations are chosen with a bias towards nearer systems but better prices for more distant targets of course.
Players can buy cargo for the source price, and will get the destination price when they deliver it to the right place. Since any one star system will normally contain a random assortment of cargo for different destinations, it's very wrong to buy a full train and then deliver each truck to its final destination.
The skill, of course, is in choosing cargo which matches your plans, plus any that can be traded with other players you expect to meet (cargo can be traded just by being in the same system, it doesn't need a 1:1 encounter). Trading with players is by maintaining a sell price, normally increasing as the destination is approached, and allowing anyone to buy.
When a cargo module is sold at the destination it goes into an invisible waiting state for some turns before re-appearing as a new cargo module at that star system. The wait is much longer for contraband, and is in any case modified by the government type (the Federal government for locations inside the Federation, the local alien government otherwise). So, excessive contraband trade can lock up most of a region's cargo in wait queues, preventing any other sort of trade, and excessive militarism in the government is also bad for trading profits.
Unbought new cargo is regenerated each turn, so players can avoid contraband or unsuitable cargo by waiting for it to cycle into something else. There are no trade-routes in the tedious repetition sense, but players can construct trade centres by choosing cargo that terminates there. There's a probably a bias toward cargo modules wanting to return to their original creation point, to prevent players permanently shifting all the cargo from one region to another.
In areas of high density trading it may be feasible for some players to specialise in stationary trading, ie dispense with warp drives in favour of a space station which buys and sells large amounts of cargo each turn allowing ships passing through to quickly filter their mixed trains for single-destination convoys. Such juicy targets inevitably create more ecological niches for bandits and stationary sheriffs.