[教學][討論]如何洗牌才不會卡？

[twn_domn]

這個問題，除了聊天區聊起來以外，其實很多人早就在研究這個問題了。

我想，很多人都能提供出所謂的「撇步」，但是也沒辦法證明。之前那位寫 hypergeometric distribution ﹝魔風機率的文章，在精華區﹞的作者，也提到這個問題。

http://www.kibble.net/magic/magic09.php

原文在此：

Probability: Shuffling and Randomization

Since Magic is supposed to be played with a randomized deck of sixty or more cards, the issue of shuffling presents itself at the beginning of the game, as well as some situations within the game that require shuffling. What constitutes fully randomizing a deck? The three most common shuffling techniques used by players are riffle shuffles, pile shuffles, and overhand shuffles. A riffle shuffle is when the deck is divided into two halves and riffled together, alternating one card from each. A pile shuffle is when the deck is dealt out into a number of piles and then grouped back up. An overhand shuffle is just taking part of the deck and moving it to another part of the deck, such as taking a few cards from the middle and moving them to the top or bottom, over and over.

Obviously the overhand shuffle is the least effective shuffle, as "clumps" of cards (that is, small groups of cards) tend to stay together more often and not get randomized in this method. The riffle shuffle and pile shuffles are indeed the methods that professional players use. Simply put, these methods randomize the deck to a much higher degree. Pile shuffles vary among players. Some like to use four piles, while some use seven. I have seen higher-end players use seven piles. This is effective because clumps are nonexistent in this method. Any group of seven cards becomes completely divided using this method. Combined with a few riffle shuffles, this randomizes a deck to a great degree.

How good is a riffle shuffle, though? To randomize a deck of 52 playing cards, it only takes 7 times(1). With 60 cards, it should therefore take approximately 8 shuffles. When many players play a game I often see them overhand shuffle once or twice, and feign a riffle shuffle. These players then draw land after land and wonder why! According to the same web site, it would take 2500 overhand shuffles in order to get the same randomization as 7 riffle shuffles! Again my analysis holds true: Riffle shuffling is a supremely effective shuffling method. When playing a game, the best thing to do is probably pile shuffle with seven piles first, in order to mix up your deck from the previous game. After that, three or four riffle shuffles are incredibly effective. Seven or eight riffle shuffles before each game can be incredibly tedious, but the existence complete randomization is still shaky. Therefore coming close to complete randomization is the best one can do.

Even though pile shuffles and riffle shuffles combine to create a good shuffling technique, there will always be the chance of drawing no land cards or all land cards. However, that is part of being randomized, and will happen every so often. Because of this, the DCI created the Mulligan rule. That lets players shuffle their initial hand into their deck at the very beginning of the game if they are very unpleased with it. The penalty is that their new hand consists of one fewer card. This is a great idea, because the chance of drawing no land twice in a row is very slim. In the next section, I will analyze such probabilities in depth using hypergeometric distribution techniques.

我簡單的翻一下。
基本上，洗牌有三種：
overhand：就是最常見的。把牌的一部份整疊用一手拿起，然後放入或是插入另一疊。
pile：就是把牌一張一張的分成好幾疊，最常看到的是四到七疊，分到手上的牌都分完。
riffle：就是分成兩疊，一手一疊。然後兩手用撥的動作，把兩疊牌撥在一起。

作者接著要強調的是：雖然 overhand 最常被人用到，但是，其實 riffle 是最快也最容易得到真正的 random，也就是隨機。當然，大家都會記得用 pile，可是 pile 很費時。所以，他建議先 pile 一次，然後再 riffle 幾次。

[E-Elemental]

riffle：就是分成兩疊，一手一疊。然後兩手用撥的動作，把兩疊牌撥在一起。.

所謂的撲克牌洗法嗎?好奢侈昂貴的洗法啊~心會痛的~

[flamezax]

所謂的撲克牌洗法嗎?好奢侈昂貴的洗法啊~心會痛的~

這方法我還不太會洗哩~看來要多練練~

[Gaea]

恩...提供一下
之前吉龍撥看日本人好幾個都是分6-8次
他們手腳很快直接把牌灑在桌上
8分,7分,8,7,8,7....
當然我不知他們是不是都一值降子洗
可是當時看到籐田肛門跟森田雅雁差不多是降子
3年前森田也差不多是這樣洗
而我個人是習慣先分一半插入另一半好幾次
再8分,再7分,再插好幾次

這方法我還不太會洗哩~看來要多練練~

[E-Elemental]

可是當時看到籐田肛門跟森田雅雁差不多是降子

籐田肛門? 好難聽的名字啊~

[twn_domn]

所謂的撲克牌洗法嗎?好奢侈昂貴的洗法啊~心會痛的~

付了報名費，收了卡組套牌，結果還卡地輸，才心痛啊！

[Gaea]

開玩笑的
沒有特別意思

好難聽的名字啊~

[孤鷹]

會不會卡這個問題，應該是看對手的洗牌手法吧！

記得早期，遇到非常重要的比賽。
我就會使用前輩留傳下來的三分法或二分法。

現在，就真的很少使用這招了！
因為真的太陰了！

話說鋼彈大戰現在連洗牌方式也有制式規定！
真的是讓人覺得OOOXXX！

BY 孤鷹！

[理卡路德]

唉唉..沒想到一小段抱怨..反掀起如此波濤= =
還被一堆人罵..
>聽起來像是做賊的喊抓賊
>或者說是小偷遇到強盜頭子
>私底下愛怎麼分都可以，比賽時請保持套牌隨機化吧
>而就算你實在是一天都被地神詛咒，一定要二一插才打的下去
>被對手抓包三分時，請不要反而埋怨對手

也如孤鷹所說..早期被對手三分真的會OOXX..
公認是陰招..小手段
現在卻成了"大公至正"..時代果真會變

我後來個人是採用"四六分法"..
先分四堆~再分六堆..也從沒看對方有意見過..
而GW是規定要"十分法"..DECK規定50張..
雖麻煩..但也算是一種公平制度..

[frederick]

只要你有真的「洗牌」，會不會卡就完全是運氣的問題。
如果套牌真的隨機化了，那就有一定的機會會卡。
這就好像樂透一樣，開連號有沒有可能？當然有。
如果今天樂透機上標示：絕不開連號
那豈不是作弊？

[twn_domn]

只要你有真的「洗牌」，會不會卡就完全是運氣的問題。
如果套牌真的隨機化了，那就有一定的機會會卡。
這就好像樂透一樣，開連號有沒有可能？當然有。
如果今天樂透機上標示：絕不開連號
那豈不是作弊？

那句話應該改成下列：

只要你有真的「洗牌」，會不會卡就完全是機率的問題。
這就好像樂透一樣，開到你買的號碼有沒有可能？當然有。
如果今天樂透機上標示：絕不開你買的號碼
那豈不是作弊？

也就是說，如果你洗的方式正確，那當然還是有卡的機率，只是會變的很低。

[肥肥]

什麼是三分法呀?!
為什麼有涉及到作弊問題?!
---------------------------------
我洗牌方式是先把牌分為一張地兩張其他牌直到分玩為止,
然後再進行洗牌....
這樣算作弊嗎?!

[孤鷹]

什麼是三分法呀?!
為什麼有涉及到作弊問題?!
---------------------------------
我洗牌方式是先把牌分為一張地兩張其他牌直到分玩為止,
然後再進行洗牌....
這樣算作弊嗎?!

在比賽時，是不允許你這樣做的！
因為套牌沒有亂數化。

所謂的三分法，就是將套牌依一次一張的分法。
將套牌分成三份，在混合洗在一起。

其他的二分、四分、五分至十分法，依此類推。

BY 孤鷹！

[肥肥]

那為什麼三分法亦或二分法會很陰?!(這樣不是洗不乾淨了嗎?)
而且對手不是有權幫你任意洗牌嗎?!

[喵喵]

因為你如果料兩張 地一張的這樣插
他幫你三分法...
你就會發現 你的地都在同一疊裡
然後他把牌還你 你最多也只能再切一次牌
卡到死