Description
Players shout out bids as they will, with no turn order. While an Open Auction will typically end when a certain amount of time with no increases occurs or it becomes clear that no one wishes to raise the current bid, a true Open Auction allows a seller to accept any bid at any time and close the Auction. Tough the usual outcome is that the high bidder is the winner, no rule requires this outcome.
Discussion
An Open Auction is quite unusual in that it has no auctioneer and no rules—not even the rule that the highest price must win. In a sense, an Open Auction is more like an out-loud simultaneous negotiation. The reality is that very few auctions, in the real world or in board games, are truly open. That is because Open Auctions are pretty messy! Multiple bidders often want to bid the same amount, and the bidding increments can be all over the place. Some bidders may not hear all the bids, and confusion is all too common. Without an auctioneer, these auctions can be difficult to govern fairly. In the board game context, it is worth pointing out that they also tend to be really noisy and frenetic. The only game we could find that uses anything like an Open Auctions is Monopoly. In perhaps the most-overlooked rule in the game, when a player decides not to buy a property from the bank, the property is sold to any player (including the one who chose not to buy it from the bank initially) at any
price. Monopoly does specify that the Banker auctions the property and must sell to the highest bidder but no other rules on how to govern the auction are provided. Despite their weaknesses, Open Auctions do have some important features. First, iterative bidding provides a lot of information as players reveal their preferences and for the goods up for auction. The auction integrates a means for allocating resources with a way for players to trade opinions about how valuable they are. Another important feature of the Open Auction is that the dominant strategy for any bidder is to stay in the auction until their value for the auctioned goods is reached. This means that absent external issues, like very large disparities in player wealth, or a bidder risking bidding up the price past their valuation, the winner will pay a price close to the actual value for the item—or, to be precise, they will pay, at most, one dollar (or other bidding increment) more than the price at which the second-highest bidder valued the item. In general, Open Auctions are more theoretical than practical. There are many small tweaks to the basic structure that create much more suitable dynamics for use in tabletop games. We include the mechanism of Open Auctions here as a foundation on which to build.
Sample Games
Monopoly (Darrow and Magie, 1933)
描述
玩家随意喊出依自己的出价，没有回合顺序。虽然公开拍卖（Open Auction）通常会在一段时间内没有增加或很明显没有人希望提高当前出价时结束，但真正的公开拍卖允许卖方随时接受任何出价并结束拍卖。尽管通常的结果是出价最高者获胜，但没有规则要求这一结果。
讨论
公开拍卖非常不寻常，因为它没有拍卖师也没有规则——甚至没有最高价格必须获胜的规则。从某种意义上说，公开拍卖更像是一种大声的同时谈判。现实情况是，在现实世界或棋盘游戏中，很少有拍卖是真正公开的。这是因为公开拍卖非常混乱！多个竞标者经常想要出价相同的金额，而且竞标增量可能到处都是。有些竞标者可能听不到所有的出价，混乱太常见了。没有拍卖师，这些拍卖很难公平地管理。在棋盘游戏背景下，值得指出的是，它们也往往非常嘈杂和疯狂。我们能找到的唯一使用类似公开拍卖的游戏是《大富翁》（Monopoly）。这是游戏中也许最被忽视的规则，当玩家决定不从银行购买房产时，房产将出售给任何玩家（包括最初选择不从银行购买的玩家），以任何
价格。《大富翁》确实规定银行家拍卖房产并必须出售给最高出价者，但没有提供关于如何管理拍卖的其他规则。尽管有弱点，但公开拍卖确实具有一些重要特征。首先，随着玩家透露他们的偏好和对拍卖商品的偏好，迭代竞标提供了大量信息。拍卖整合了一种分配资源的手段和一种玩家交换关于它们有多大价值的意见的方式。公开拍卖的另一个重要特征是，任何竞标者的优势策略是留在拍卖中，直到达到他们对拍卖商品的估值。这意味着如果没有外部问题，比如玩家财富的巨大差异，或者竞标者冒着将价格抬高超过其估值的风险，获胜者将支付接近该物品实际价值的价格——或者，准确地说，他们最多将支付比第二高竞标者对该物品估值的价格多一美元（或其他竞标增量）。一般来说，公开拍卖在理论上多于实践。对基本结构有许多小的调整，可以创造更适合在桌面游戏中使用的动态。我们在这里包括公开拍卖的机制，作为构建的基础。
游戏范例
Monopoly (Darrow and Magie, 1933) - 《大富翁》