Obviously, the rotors had to be marked in some way on the outside so that the different positions could be identified.
转盘外面必须用某种方式做上标记，以便识别它当前的状态，
However, here entered yet another element of complexity.
于是这又增加了它的复杂性。
Each rotor was encircled by a ring bearing the 26 letters, so that with the ring fixed in position, each letter would label a rotor position.
每个转盘都镶着一圈金属带子，带子上依次铭刻着26个字母，当带子在转盘上固定好之后，一个字母就代表着一个盘位。
(In fact, the letter would show through a window at the top of the machine.)
机器上方有小窗口，可以看到代表当前盘位的字母。
However, the position of the ring, relative to the wirings, would be changed each day.
然而，字母与电线之间的对应关系是可以改变的。
The wirings might be thought of as labelled by numbers from 1 to 26, and the position of the ring by the letters A to Z appearing in the window.
用数字1-26来表示电线，用窗口上显示的A-Z来表示转盘的位置，
So a ring-setting would determine where the ring was to sit on the rotor, with perhaps the letter G on position 1, H on position 2, and so forth.
通过带位设定注，就可以决定它们的对应关系，比如令字母G对应1号线，字母H对应2号线，等等。
It would be part of the task of the cipher clerk to make the ring-settings, and thereafter he would use the letters on the ring to define the rotor-settings.
带位设定是密码操作员的工作，然后他可以用窗口上的字母来表示当前的盘位。
From the cryptanalyst's point of view, this meant that even if it were openly announced that rotor-setting 'K' was being used, this would not give away what at Bletchley they would call the core-position—the actual physical position of the wiring.
从密码分析的角度看，这意味着即使公开宣布正在使用盘位K，也不会泄露布莱切利所说的核位模式，也就是电线的连接关系。
This could only be deduced if the ring-setting were also known.
只有同时知道盘位和带位时，才能推导出相应的核位。
However, the analyst might know the relative core-positions; thus settings K and M would necessarily correspond to core-positions two places apart.
不过，如果分析员知道盘位，而且带位是不变的，那么他就可以得到一个相对核位。
So it was known that if K were at position 9, then M would be at position 11.
比如说，假定K在9号线上，那么M就一定在11号线上。