Fast cavalry can perform great feats of speed and manoeuvre, being able to reform once as they move, even when marching! This enables a unit in a column to deploy to its left and right in a single line as shown.

The first thing to note is that the unit has deployed as equally as possible around the front model. It would deploy about the middle model in the front if the unit were formed into a wider column. Units changing their frontage rapidly in this way always do so about the centre front model. This applies equally to units forming a column from a line, or otherwise adding or reducing ranks to lengthen or shorten a line (see Fig. 6).

The second thing to note is that the models at the rear of the column have actually moved a long way! The longer the column the further they move. This is not a problem in itself - fast cavalry are supposed to be fast and manoeuvrable after all but it can become a problem if the column is very long, say 20 models for example.

For this reason, when deploying from a column into a line, models must be within their Movement distance of the position they want to occupy in the front rank. Models may not move further than their Movement distance in order for the unit to redeploy, so the frontage of the unit will be reduced as a result.

The third point is that models moving from the rear of the column might find their most direct path blocked by difficult terrain, by obstacles or other troops. In this case models must be able to trace a clear path to their new position without having to cross the difficult terrain/obstacle/troops, and they may not travel further than their Movement rate to do so. Fig. 7 shows how this happens when a column rides past and behind an enemy unit, then deploys into a line.

As a general rule, if models at the rear of a formation cannot trace a path to their intended position without moving into difficult terrain, crossing an obstacle, or moving through other troops then the unit cannot redeploy as intended.