Overwatch

2nd Edition WH40K Rules for Overwatch

From 2nd ed. rulebook p. 39

OVERWATCH

Overwatch is a special rule that allows models to forgo their own turn in order to shoot during the enemy's turn. This is very useful as it allows you to set up ambushes and fire traps for advancing enemy troops. (...) As troops advance it is a good idea for squads behind them to take up a position where they can shoot at the enemy as they appear. In this way friendly advancing troops are protected by those behind who remain still, watching out for the first sign of the enemy, scouring the terrain for the slightest glimpse of movement. This is represented in the game by the Overwatch rule. It is mostly used to shoot at enemy troops as they emerge from cover, or as they move from one piece of cover to another. It also allows two squads to move forward and mutually protect each other - first one moving while the other uses overwatch, then reversing roles, one squad moving forward under the protection of the other.

PREPARING OVERWATCH
The player decides which troops are going on overwatch at the start of his turn. Only whole squads can go into overwatch, it is not possible to place some models out of a squad into overwatch while other models move and/or fire. Vehicles and characters may go into overwatch. An Overwatch counter is placed next to troops on overwatch as a reminder. Models on overwatch may do nothing during their turn: they may neither move nor shoot, for example. The Overwatch counter remains in place, so that the model is still on overwatch when it comes to the opposing player's turn.

FIRING ON OVERWATCH
A model or squad on overwatch may shoot during the opposing player's following movement phase. Troops on overwatch may shoot at targets as they present themselves at any time during the movement phase. For example, a model can be shot at before it moves, after it completes its movement, or at any time in between. A target which doesn't move at all can still be shot at so long as it can be seen. The most common use for overwatch is to shoot at enemy as they move from to cover to cover, where they would normally be hidden during the shooter's own turn. Overwatch can also be used to ambush troops as they move into range, denying them the chance to reach cover. Troops may not throw grenades as part of overwatch fire.

As soon as a model or squad shoots its Overwatch counter is removed. Work out whether the shot hits and damage as normaland then proceed with movement. There is one extra modifier taken into account in overwatch fire.

-1 Shooting at a model which is either emerging from or moving into cover, or which is charging the shoother
This modifier only applies to troops on overwatch. It applies if the target's intended move will take it into cover, or if it emerges from behind cover. It also applies if the tagret is charging the model on overwatch. This is the only time when a model which has been charged can shoot at his attacker as he closes. This takes into account that the target is visible only for a brief moment, or that the shooter is flustered by the enemy's charge. Note that the -1 does not apply twice if a target jumps from behind cover and charges the shooter, it is only ever applied once. Overwatch fire at models charging into hand-to-hand combat always takes place at short range for whatever weapon the overwatching model is using.

LOSING OVERWATCH
Unused Overwatch counters are removed at the start of the player's own turn. New Overwatch counters may the be placed as required. A model can stay on overwatch from turn to turn so long as neither side moves or fires, but it will save confusion if old counters are removed and new ones placed.

Troops shoot at while on overwatch must immidiately take a Leadership test as follows. Roll 2D6 - if the score is equal to or under their Leadership charateristic they have passed and all is well. If they roll more than their Leadership they fail the test and lose their Overwatch marker.

As soon as the Overwatch counter is lost the model or squad reverts to the normal game sequence. Note that you don't have to hit the target to force a Ld test - it only has to be shot at.

This rule represents troops being forced to duck and flinch by enemy fire. This is not likely to happen often as models on overwatch will usually fire before the enemy (ie in the movement phase which comes before the shooting phase). However, it is possible for a model to be hit by an off-target friendly weapon during his own shooting phase.

It is most likely that a model on overwatch will be shot at by an enemy who is also on overwatch during his own movement phase. In this way squads can give 'covering fire' for their compatriots by keeping the enemies' heads down whith their own overwatch fire.