One element is removed for each hit received by a unit, either from HTH or shooting. If a unit passes its subsequent morale test, the remaining elements must, if necessary, be moved to keep the unit together, and if in HTH the unit must also maintain contact with the enemy.
The player controlling the unit determines which elements are removed, they do not have to be the actual element 'hit'. A unit providing an overlapping element is eligible to take casualties.
It is usual to remove the rear rank of a column and the end of a line but units must maintain contact with any enemy, extra movement is allowed for this purpose. A unit cannot gain an advantage from taking a casualty.