巴格拉斯本人是有书的，里面确实解密了原版的巴格拉斯的秘密，但也仅仅是解密而已，一般人甚至一般的魔术师知道了也无法复现（巴格拉斯本人说需要经验丰富的魔术师练习两年大概可以去表演），而且这个魔术也不存在百分百成功的方法。如果不想自己去读纯英文的书可以看看外网一些大佬的简短版总结：（看不懂可以翻译）
The Berglas effect is completely explained in the book handily titled “The Berglas Effect” by (I think from memory David Kaufmann)
I can assure you that it is a genuine trick in the sense that the 2 people who name the card and it’s position are not stooges, and it takes immense skill on the part of the magician. The explanation takes 50 pages of the book so it’s not easy to summarize. Berglas himself says that an experienced card magician will take about 2 years to learn the trick including practice sessions every day.
First, you should understand that the trick actually starts before the cards are even removed from the box. Didn’t some magician say that “just when you think the trick has started, it reality it’s already over, and all the magician has to do is present some pretty patter”.
To greatly oversimplify, it relies on a fantastic use of memory. Yes, the deck is stacked & the m. knows exactly where every card is positioned at the star t. Bear in mind that most magicians use a standard way of creating the stacked deck, such as that from the “English Magic Club”. B. himself uses six different stacks.
The magician never actually touches the cards himself. His first task is to track the position of the the wanted card whatever happens to the deck in terms of shuffling & cutting etc. You simply have to read the book to understand how this works, AT the end of the first part he knows the exact position of the card, now “ALL” he has to do is get the second person to name the correct position eg. “IT’s the 27 card”. He uses all kinds of techniques to achieve this. For example, if he knows the card is the fifth card, he might say something like “Give me a number, a small number” & if he’s desperate he might say “between 1 & 10”. This is the basic principle but the actual techniques that are used are much more refined.
ANd yes, it goes wrong sometimes. B. has all kinds of clever getouts to cover this (including the situation where the first person simply forgets the name of the card he has chosen) but if he’s desperate he will actually shuffle the cards himself, and he is so adept that he can reposition the card where he wants (the trick then becomes any-card-at-any-number)
Get hold of the book. Your local library may not have it in stock, but they can probaly get a copy for you.

刘谦的效果明显比原版巴格拉斯更好，在场的魔术师不知道是不是托，反正肯定没有想为难刘谦，至少说的都是比较折中的选项（真想为难刘谦就会报一个比较极端的数字），考虑到刘谦没有洗过牌，说不定他们报的都是各位顶级魔术师之间约定俗成的数字呢（毕竟巴格拉斯效果这种东西也不是一般魔术师会去交流讨论的）但无论如何，从最终结果上来看他们成功为魔术界留下了轰动后世的悬念（我想这不会对在场的各位知名魔术师有任何利益损坏）。所以刘谦版本的巴格拉斯只能说自己见仁见智了。
对了，刘谦的电视版本（非直播）的巴格拉斯效果明显是有剪辑的，不清楚原因，但是我想播出到电视的娱乐节目，导演是不会允许出现节目失败的吧？