作者：trac.bookofhook

正如我在本系列的第1篇文章中所说的，标准化货币减少了不同经济参与者（玩家和NPC）之间的交易摩擦。本文将继续讨论游戏中的NPC商人在经济系统中的作用。（请点击此处阅读本文第3篇）

NPC商人

我们通常认为NPC商人是“购买我打怪获得的垃圾以及将好东西买给我的家伙”，但商店老板只是商人的一个类别。NPC商人其实表现为游戏中的任意实体，只要是接受东西然后再返回服务或商品的NPC都可以叫作“商人”。例如，任务发放NPC—-他可能只接受一种东西（“任务令牌”），然后返回任务结果—-这也是一种NPC商人。

无论是上述的哪一种商人，这种NPC角色的作用都是，从玩家手中拿走有形货币和/或商品，再将其转化为其他东西（金币或其他商品）。虽然最典型的例子还是商店老板，我之所以觉得有必要提一下任务发放者，是为了指出商店老板并不是唯一一种NPC商人。

货币和商人

Merchant(from e2bn)

无论是出于什么意图或目的，在没有标准化货币的情况下是不可能使商人发挥作用的。商人没有物物交换的智慧，这意味着设计师必须借助预设的菜单和价格表（游戏邦注：除了NPC任务发放者，他可以只有一个代码编写好的交易表格）。

商人提供两个实用的功能：第一是，给玩家提供清算场所—-出售掉落物品和旧商品，在这个过程中，物品被转化为货币，同时将旧商品从经济中移除；第二是出售已知商品和（可能的）一致的代价，从而引导经济和约束价格。例如，商店是一个有保证的市场，这意味着如果你花了很多精力制作或收集某物，你必然会因此得到相应的经济奖励（假设NPC商人都不挑剔自己出售什么或收购什么）。

有趣的是，NPC商人和标准化货币是互相参照的。也就是说，如果你移除一种，那么另一种也必须移除，但如果你同时移除二者，你的经济系统仍然可能正常运作—-只要移除二者后产生的间隙得到弥补（即只有商人提供的商品和服务现在可以通过其他方式获得）。

商人作为转换器

在具有货币和商人的虚拟经济中，后者起到关键作用：转换器。他们将商品转化为货币，再把货币转化为商品，这个过程通常要消耗一定的摩擦成本（比如，你用10金币购买一把长剑，但卖掉长剑只能得5金币）。

转换有许多方便的副效应：

玩家可以轻易的将物品转换为金钱或买回物品，这就“润滑”了经济，方便玩家交易。

不使用的物品不会污染游戏世界，相反地，它们被转化为相对惰性的和可压缩的现金。

钱不会闲置，可以轻易地转换为对特定玩家具有价值的物品。

某玩家认为无用的物品可以通过作为中介的商人（假设这个商人出售物品）转移到其他玩家手中。

基本上，商人增加了交易活动的便利性和高效性，从而使游戏世界产生实用的货币系统。通过购买商品（把它们从整体流通中取出），商品的污染性减少了，避开有害的副效应，如强大的道具与低级角色之间的频繁交易。

商人作为价格调控器

在玩家驱动的经济中，商人还起到价格调节器的作用。如果玩家是经济结构中的重要部分，通过玩家之间创造、出售和购买商品中和服务，那么总有“滥用”的可能—-当玩家主宰了某个经济方面并利用它影响其他玩家。

如果获得钢铁巨剑的唯一办法是从铁匠处购买，如果钢铁巨剑只被某些玩家认为是最好的武器，那么铁匠可以互相勾结以哄抬价格，使原来价值一金币的东西变成二十金币。NPC商人可以防止这种“卡特尔”（游戏邦注：Cartels，是指一些生产相同产品或服务的厂商,一起合作来控制这类产品或服务的市场。），虽然这让从事这门手工艺但不想与“电脑”竞争的玩家感到愤怒。如果NPC商人以三金币的价格出售给你完全相同的钢铁巨剑，那么价格上限就确定了。这样，铁匠们就无法过分抬价了，比如定个看似更合理的五金币的价格，同时咒骂多管闲事的游戏设计师。

类似地，价格下限也确定了，尽管这更少见（让买家团结起来通常比让卖家勾结起来更困难）。

也就是说，价格调控更多地表现为市场便利性而不是必要性（尽管玩家受垄断支配的玩家的感觉相反），因为大部分垄断都是不稳定的：强制无人能承受的价格是自掘坟墓的行为，结果是垄断团体中的一员以低廉的价格出售开始崩溃的商品。在足够庞大的游戏世界中，自由市场要求商品以比较公平的价格出售—-缺少来自那些促成现状的因素的威胁（卡特尔、垄断、公会、联盟、政府，等等）。

商人作为替代者/初始市场

在虚拟世界中，由电脑制作、购买和出售服务和商品；当这个世界第一次形成时，会产生一个鸡生蛋的问题。一个“新生的”世界没有使经济运转起来的必要技能和商品。唯一的资源来自自然环境，如果玩家想要某种先进的物品，而没有电脑工匠会制作，那么他就不走运了（会感到沮丧）。

NPC商人可以通过启动经济泵或提供替代市场去缓和这个问题。NPC在游戏经济中可以扮演初始买家和卖家，从而减轻贫穷、无能但想建立原始经济的玩家们的负担。

另外，通过直接提供商品（以相对高的价格），NPC商人使玩家跳过了许多无聊而漫长的等待时间。比如，玩家不必等铁匠一周的时间做出钢盔，而是立即向NPC商人购买（虽然价格更高一点，品质更差一点）。之后，当铁匠掌握了制作钢盔的技艺，他的产品自然而然会排挤掉NPC商人的商品。

在最糟糕情况下，初始经济造成的商品短缺问题可能非常严重。如果所有食品都只能向NPC面包师、屠夫和农夫购买，那么可怜的术士就要饿死了，因为可以卖给他食物的人都不在线。当理想的市场不合作时或干脆不存在时，NPC商人的作用就是提供一个低效运作的替代品市场。

如果没有这种替代品市场，玩家群体可能永远也无法达到群聚效应，而这种效应是建立合适的电脑驱动的经济所必需的。

供求模型

虚拟经济的一个问题是，设计师总是忍不住向现实世界靠拢。这是一个危险的倾向，因为虽然虚拟世界和现实世界让人觉得是类似的，但它们其实是完全不同的。

我的建议是“建立一个供求模型”。这么做的目的在于，为获得的或收集的一般物品设置可以接受的价格，并且让人觉得现实。例如，一个靠近铜矿区的小镇可以遇到铜矿供大于求的难题，这样当地的商人可能不愿意拿任何东西交换铜矿。

这是说得通的，但它确实使玩家讨厌，玩家虽然理解且甚至同意这种逻辑，但并不希望它发生。相反地，他们会抱怨自己费了这么大力采矿，结果得到的却是一堆换不了钱的铜矿—-除非他们乐意跑到缺铜矿的地区并在那里出售。这个建议当然有一定的吸引力，但很不幸，过程是非常沉闷的。

相反的情形也可能发生。如果有一个小镇没有面包师、屠夫和农民，玩家可能发现食物非常匮乏，且价格相当高。一时间，低级玩家都吃不上饭了，甚至高级玩家的冒险也很难展开，因为他们的战利品全都换成食物了。是的，这在现实中是非常可能发生的（传说在淘金潮时期，矿工要花一美元才能买到一个鸡蛋），但再者，这太无趣了。

总之，在一个大经济导致平衡各种市场的套利专家出现的世界里，建立本地供求模型是可行的。但这有许多要求，包括一系列设计师可能预测到但无法保证的自然行为。

总结

在游戏世界里，约束性经济要求具有若干种将商品转换为货币和把货币转化回商品的媒介。NPC商人就具有这种功能，还附带了一些次要好处，如稳定经济。虽然NPC商人不一定是必须的，但他们可以通过代替电脑、调控价格和提供急需的关键资源，使经济运行更加顺畅。

如果你的经济系统没有标准化货币，那么NPC商人在很大程度上就失效了，因为这个经济系统会自动转变成一种物物交换系统。

（本文为游戏邦/gamerboom.com编译，拒绝任何不保留版权的转载，如需转载请联系：游戏邦）

The Design of Online Economies

by trac.bookofhook

Part 2: NPC Merchants

As I discussed in Part I: The Role of Currency, standardized currency reduces the transactional friction between different economic participants: players (PCs) and non-player characters (NPCs). This article addresses the function (and ramifications) of NPC merchants in an online economy.

NPC Merchants

Traditionally we view NPC merchants as “that guy that buys the crap I loot of monsters and sells me better swords”, but that the shopkeeper form is just one specific type of merchant. An NPC merchant is really any game entity that, when given an item, performs a service or returns a good. For example, quest giver NPCs — who may take only a single type of item (“quest token”) and give something back in return — are a type of NPC merchant.

Either way, the common element is that a non-player character takes tangible money and/or goods from a player and converts it to something else (money or another good). And while the most common examples are, in fact, shopkeepers, I feel obligated to mention the whole quest giver thing just so to emphasize that shopkeepers aren’t the only form of NPC merchant.

Currency and the Merchant

For all intents and purposes it is impractical to implement merchants without a standardized currency. They lack the intelligence to barter for items, which means designers must fall back to a predetermined menu and price list (except for NPC quest givers, who can probably just have a hardcoded exchange table).

Merchants serve two useful first-order functions. First, they provide a handy clearinghouse for players selling acquired loot and old items — in the process converting items to currency while removing old items from the economy. The second function is to offer goods at a known and (presumably) consistent cost, bootstrapping the economy and setting price constraints. For example, shopkeepers are a guaranteed market, which means that if you expend a lot of effort to make or harvest something, you’ll get some financial reward for it (assuming most NPC merchants aren’t picky about what they buy and sell).

It’s interesting to note that NPC merchants and standardized currency reference each other cyclically. If you remove one, then the other must be removed, but if you remove both at once, you can still have a functional economy so long as any resultant gaps are filled (e.g. items and services that were provided solely by merchants are now available through other means).

Merchant as Transformer

In a virtual economy with currency and merchants, the latter play the vital role of transformers. They transform items into currency and back, usually with an associated friction cost (you buy a long sword for ten gold pieces but can only sell it back for five).

Transformation has a lot of handy side effects:

players can easily convert items to cash and back, which increases player convenience and “lubricates” the economy
unused items don’t pollute the world, instead they are converted to relatively inert and compressible cash
money does not lie fallow, it can easily be converted into items of value for a particular player
items that one player may find useless can propagate to other players using the merchant as a vector (assuming the merchant resells the item)
In essence, merchants make a currency system practical by providing the transformation facility and increasing economic efficiency. By purchasing items (and taking them out of general circulation), item pollution is reduced, staving off deleterious side effects such as a constant shift of high powered items to lower level characters.

Merchant as Pricing Regulators

Merchants also fulfill the important role of pricing regulators in a player driven economy. If players are an important part of the economic structure, by creating, selling, and buying goods and services between each other, then there is always the opportunity for “abuse” when players with control over a particular economic facet use it as leverage against other players.

If the only way to acquire a Steel Bastard Sword is to purchase it from a smith, and if the Steel Bastard Sword is simply the best weapon for a given group of players, then smiths that collude with each other can drive the price through the roof, selling an item that cost, say, one gold piece for twenty gold pieces. NPC merchants can prevent such cartels, much to the ire of PCs that engage in crafts and dislike competing “with the computer”. If an NPC merchant will sell you a functional equivalent to the Steel Bastard Sword for only three gold pieces, then a price ceiling is established. The smiths will have to drop their prices to, say, five gold pieces in an attempt to look reasonable, all the while cursing the meddling game designers.

Similarly, a price floor can be established, although this is much more rare (it is usually much harder for buyers to organize than it is for sellers).

That said, price regulation is more of a market convenience than necessity (although players at the mercy of a monopoly may feel otherwise), because most monopolies are unstable: it’s self-defeating to enforce prices that no one can afford, and all it takes is one member of the monopoly to undercut everyone else for things to start crumbling. And in a large enough on-line economy, there will come a point where free-market properties end up dictating the fair price for goods — short of threats from those with an investment in the status quo (cartels, monopolies, guilds, unions, governments, and their ilk).

Merchant as Substitute/Initial Market

In an online virtual world where PCs are expected to create, buy, and sell the bulk of services and merchandise, there is a pronounced chicken-and-egg problem when the world first launches. A “fresh” world has no one with the requisite skills or items to get the economy rolling. The only source of “stuff” is from the environment, and if a player desires a specific advanced item and no PC crafter is able to make that item, then he’s out of luck (and very frustrated).

NPC merchants can ameliorate this problem both by priming the economic pump and providing a substitute market. NPCs can act as the original buyers and sellers in an economy, thereby reducing the grid lock between relatively poor and powerless players trying to establish a primitive economy.

In addition, by providing immediate access to goods (at relatively high prices), NPC merchants allows PCs to skip much of the tedious delay waiting for the economy to ramp up. Instead of waiting a week for Bob the Smith to make a steel helmet, Will the Warrior can buy a (more expensive, lower quality) steel helmet from a merchant right away. Later, when Bob has mastered making steel helmets, his goods should naturally supplant those of the NPC merchants.

In the worst case, scarcity due to a nascent economy can be devastating. If all food is available only from PC bakers, butchers, and farmers, then woe to the poor wizard starving to death because no one is on-line that can sell him food. When a desired market is uncooperative or simply non-existent, NPC merchants act as an inefficient substitute market to keep things limping along.

Without this substitute market a population may never attain the critical mass necessary to found a proper PC-driven economy.

Modeling Local Supply and Demand

One of the problems with virtual economies is that there is a constant temptation to “be more like the real world”. This is a dangerous path, because while the virtual and real worlds feel similar they often have stark differences.

One such common suggestion is to “model local supply and demand”. The intent is to look at commonly harvested or acquired local items and attempt to set prices and availability accordingly, providing a sense of realism to the setting. For example, a town near a copper mine may suffer from a glut of copper ore, and thus the local merchants may not give anything for copper ore.

This makes sense, but it really, really pisses off players who, while understanding and maybe even agreeing with the logic, don’t appreciate it. Instead they’ll curse that so much effort has been spent mining, and now they have a bunch of worthless ore — unless they’re willing to travel across the continent to a copper poor area and sell it there. This has a certain appeal, but unfortunately it’s grossly tedious.

The opposite situation can also occur. If a town has the misfortune of no local bakers, butchers, farmers, or ranchers, players may find that food is extremely scarce, and prices sky rocket accordingly. Suddenly low level players can’t afford dinner, and even high level players grouse that their adventuring is ruined because all their fat loot is being converted into food just to stay alive. Yes, this is realistic (cf. the apocryphal stories of California gold rush miners paying a dollar for an egg), but again, it’s not particularly fun.

All that said, modeling local supply and demand might be feasible in a world where a large economy gives rise to arbitrage specialists who eventually equalize the various markets. But this requires a lot of things happening, including a set of emergent behaviour that the designers may predict but cannot guarantee.

Summary

An online world that provides a sanctioned currency requires some kind of vehicle to transform items to currency and back. NPC merchants provide this ability, along with secondary benefits such as economic stabilization. While NPC merchants are not strictly necessary, they can smooth out the operation of an online world by filling in for PCs, regulating prices, and providing vital resources on demand.

If you create an economy with no standardized currency, NPC merchants are largely irrelevant since the economy will automatically transition to some form of barter system.(source:trac.bookofhook)