World Gaming Magazine

19 WGM #53 2017/12 wgm8.com WGM 本期为大家阐释期待值 （EV）的概念，这是所有高手玩 家都熟知的基本博彩概念。 WGM explains EV, a fundamental gaming concept understood by all expert players. E V 有多种叫法：预期、长期效果、合理价值、期待 值等。它并不是21点游戏的专有概念，还适用于扑 克、百家乐、花旗骰以及几乎所有的娱乐场（以及 一些非娱乐场）游戏，甚至还出现在职业体彩中。不过其 魅力在扑克和21点中有更充分的体现，因为这些游戏都需 要在玩牌过程中做出决定。当然，在体彩的注额大小上亦 有帮助。 对 EV 的最佳理解是，某个行动或决定的“即时价 值”。举个例子：假设你在21点牌桌上下注1000港币，挺 走运，拿到两张公牌，这手牌20点，而荷官的明牌是一张 6。看上去好极了！你当然不再叫牌，20点足够好了。这 手牌现在的价值是多少？如果在荷官要牌前，你必须把这 手牌卖掉，多少钱才是一个公平的价格？你当然没有百分 百的把握赢1000港币，因此合理价位应该小于1000，但具 体小多少呢？900？800？你会把这手牌的赢利卖给喊出一 口价800的买家吗？卖还是不卖？大多数人应该不卖，20 点是一手好牌，且荷官手里只有一张6。 E V has lots of names: expectation, long-run expectation, LRE, fair value or expected value. Most people tend to call it EV these days. EV isn’t a concept unique to blackjack. You find it in poker, baccarat, craps and just about every casino (and some non- casino) games. You even find it in the imprecise world of professional sports betting. It is most useful in poker and blackjack – games where significant decisions need to be made midway through a hand. It’s also useful in bet sizing for sports bets. EV is best thought of as the “value right now” of something or making a particular decision. Let us give you an example. Let’s say you place a bet on a blackjack table for $1,000. As luck would have it you get dealt two picture cards for a total of 20 and the dealer has a 6 as his upcard. You’re looking good! Of course you stand on your 20. What is this hand worth at this moment? If you suddenly had to sell this hand before the dealer drew his cards, what would be the fair price? Of course you’re not guaranteed to win $1,000, so the fair price has got to be less than $1,000, but how much less? $900? $800? Before you read on, think about it – would you sell the winnings of this hand to someone for a flat $800? Yes or no? Most people would answer no. 20 is a pretty good hand and the dealer only has a 6! 文卓弈 By Andrew W Scott