Area Fire and No Spotting

Had a great game on Saturday and some questions came up.

In a situation where an enemy unit is occupying a building and the enemy rifle squad in front of, but outside of the building, has never had a  line of sight to the occupying unit previously,  and so technically, doesn't know it is there.

Of course, as players, we can see everything. but the model units on the table, however, have know idea that the enemy are in the building 200 yards away.

So, how would we justify the Open Fire order using Area Fire to pin an enemy that we don't know about? Or, if there are a number of buildings and the enemy is in just one of them , how would the firing unit know which house  to target with area fire without some form of spotting first?

Thanks in advance, any thoughts would be great?

Area Fire isn't about shooting AT a unit but around it. Call it reconnaissance by fire if you like. You don't have to have ever spotted a unit because it's on the table already and as players we know it's there. That's just how the game works. There are some special rules for hidden units in the Blitzkrieg book that adjusts this a bit and they work very well, but probably should be used primarily in Attack/Defense scenarios.

Thanks, understood.

So if there are three houses , one of which is occupied, they will all receive area fire during an open fire order.

No, you still have to declare your shot at a unit, and unless they are spread throughout three buildings (highly unlikely) then you can only Area Fire one per action.

wouldn't the player always know which house they are in but in the real world, the soldiers would have a 1 in 3 chance?

sorry about so many questions.

If that is the way it should be , then I am vary happy with, just confirming really

Some games use hidden troops which really can slow down game play but Battlegroup does not. This is a war game and not the real world so things are done according to rules. In this case you know the troops are there because we like to actually have our nicely painted miniatures on the table rather than hidden on a map or covered by complicated if/then type rules, and Battlegroup covers this by making you roll to try and pin and then giving targeted troops a saving throw against Area Fire, and to fire Direct you must make a spotting roll first. You will find that both of those things make hitting and/or pinning units far harder than you'd think.

The rationale behind area fire and no active spotting:

Maybe one of your men saw movement of enemy running towards the building
Maybe an enemy soldier fired a few shots in your direction from the building
Maybe your NCO is experienced and realises "if I was them i'd be in this building"
Maybe someone in the building smashed a window to get better visibility

In the above cases you can target the correct building because the enemy are there - but you have not identified (spotted) them sufficiently to deliver accurate and telling fire to cause casualties.
Warfare isn't "I Go - You Go" with actions/activation's, and our troops are not un-moving miniature statues :-)

Perfect