Units can retreat or rout out of the battle square if they fail or morale check. The units of the winning side can rout or retreat also, though it is less likely. Units can rout or retreat in either the firing phase or the melee phase. A unit which routs must make a strategic move to an adjacent strategic square, which is selected at random. If it cannot make the move for any reason, it surrenders. A unit which retreats must make a tactical move of 1 to 4 tactical squares away from the battle. If a unit moved into combat, it cannot retreat in the direction it was moving, nor one direction to either side. For example, a unit which moved north into battle cannot retreat to the north, northeast, or northwest. These forbidden retreat directions are called invalid. If an enemy unit moved into the combat, then the retreating unit cannot retreat in the direction from which the enemy unit came, nor one to either side; those directions are also invalid. For example, if an enemy unit entered the combat from the east, then the retreating unit may not retreat to the east, northeast, or southeast. A retreating unit will select from among its valid retreat directions. If there are adjacent enemy units, it will not retreat in their directions; if there are adjacent friendly units not in the same square as enemy units, then it will retreat in one their directions. The unit will surrender if it has no valid retreat direction, or if its retreat move fails for any reason, including block by an enemy unit.
If a unit on the losing side has neither routed nor retreated, and thus is still in the battle tactical square at the end of the battle, then it must fall back. It will fall back exactly one tactical square, and will choose a direction using the same criteria as retreating units choose directions. Units which cannot fall back, either because they have no valid fallback direction or because their fallback move is blocked, will surrender. A unit which needs to fall back may be unable to do so if enemy units have surrounded it in the melee, even if it had a valid retreat direction. In this case the unit is trapped and will surrender.
The following messages are printed as a result of movement from routing, retreating, or falling back:
"BR1IN is unable to move." - This means a unit had to retreat or fall back, but its movement was blocked in the first tactical square it tried to move to.
"BR1IN is unable to rout/retreat/fall back and is forced to surrender!" - This means a unit that had to rout/retreat/fall back had no valid direction in which to move.
"BR1IN is exhausted, and surrenders!" - This means a unit lost a melee and had fatigue of 16 or greater.
"BR1IN is trapped by enemy forces and surrenders!" - This means that a unit lost a melee but was so entangled with the enemy units that it was unable to leave its present tactical square, even if it had a valid fall back direction available. The odds of this happening are higher if the unit had a flank turned (higher still if both flanks are turned) but it can happen even if not. This message is printed only for units falling back, not for those that failed morale checks and are retreating or routing.
"BR1IN tries to rout/retreat/fall back but is blocked, and surrenders!" - This means a unit tried to rout/retreat/fall back after combat, but all the squares to which it could legitimately move were impassible terrain, or contained enemy or neutral units, or in the case of rout, were invalid strategic moves.
"BR1IN has no direction to retreat and is forced to surrender!" - This
means that all valid directions in which a unit could retreat were blocked
by hostile units.