That is the complete keyboard. The method for using it is this: The message is written out in plain text; for example: DESTROY BRIDGE AT ONCE (Only capital letters are commonly used in cipher work.) This message is now divided into groups of two letters, in the same order, so that it reads: DE ST RO YB RI DG EA TO NC EX (The X is added to complete the group and is called a _null_.) These groups of twos are now ciphered from the keyboard into other groups of twos, by the following method: Where two joined letters of the original message appear in the same _horizontal_ row on the keyboard, the next letter to the right is substituted for each. Thus, the first two letters of our message are DE. They occur in the same horizontal row on our keyboard. Consequently, for D we write E, and for E we go “on around the world” to the right, or back to the other end of the row, and write G for E. This gives us DE enciphered as EG. Where two joined letters of the original message appear in the same _vertical_ row on the keyboard, the next letter below is substituted for each. Where two joined letters of the original message appear neither in the same horizontal nor the same vertical row on the keyboard, we imagine a rectangle with the two letters at the opposite corners, and in each case substitute the letter found on the keyboard at the other corner of the same horizontal row. This looks complicated, but in reality is very simple. For example, take the third two-letter group of our message--RO. The rectangle in this case is R D E B C F L M O and for R we substitute E, and for O we substitute L. Substituting our whole message by this system, it reads: Original DE ST RO YB RI DG EA TO NC EX Cipher EG TU EL XC AB EA GR UM IF RZ As telegraph operators are accustomed to send these gibberish messages in groups of five letters (so that they can check errors, knowing that when only four appear in a group, for example, something has been left out) these enciphered groups of twos are now combined into groups of fives, so that the finished cipher reads: EGTUE LXCAB EAGRU MIFRZ The foregoing looks extremely complicated, but the truth is that anybody, after half an hour’s practice, can put a message into this kind of cipher (“Playfair” cipher) almost as fast as he can print the straight English of it in capital letters. And unless the person who reads it knows the key word which determined the pattern on his keyboard, he would have to be an expert to decipher it, and even he could do it only after a good deal of work.