Commons cause the most trouble. Therefore everything should be
done to avoid using commons unnecessarily. In view of this try to
number the men in one continuous chain, making sure that the commons
will be between numbers at the beginning or end of the bank of
enigmas when possible. Commons should not be used fin a closure
unless absolutely necessary.
Always start numbering at the end of a chain, or part of the
menu where an odd number of enigmas converge. If numbering is
commenced where an even number of enigmas converge, it means using an
extra lead and/or common.
When a menu consists of more than twelve enigmas, and therefore
can only be plugged up twice, it is most important that the menu is
numbered twice, exactly as it is to be plugged up, i.e. according to
the numbers of the enigmas on the back of the bombe.
The I/C Ops should write the setting list at the side of the
menu sheet before handing it to the operator. This is done for two
reasons; first, it avoids confusion when there is more than one, menu
to go on the machine. Second, it avoids confusion when the menu
input on two or more machines. If the settings are on a separate
slip of paper they might get confused with the settings for another
menu on another machine.