Spells and line of sight

[Bohemond]

Sorry guys, I am confused about spells and line of sight.

Me and a friend of mine had a friendly game the other day. In his hero phase he cast a spell/prayer which targeted a point in the battlefield, while not having actual line of sight to said point. He argued he could do that, because the spell/prayer said nothing about visibility to its target. I thought this was odd. But I play Sylvaneth, and I noticed that none of my own spells say anything about visibility to its target either, so we did not debate this further.

Later I observed that the battletomes of DoZ, DoK and LoN all explicitly states which spells that requires visibility to the target. I immediately pictured myself three possibilities: 1. It does not need los if it does not mention it, thus no Sylvaneth spells need los. 2. Los should always be a general rule, even if the spell does not state anything about visibility to the target. 3. GW did a way better job at writing rules post Sylvaneth battletome.

Maybe I am overthinking this, but a clear answer to how los works with spells would be nice.

[RuneBrush]

The way I've played it is that you only need line of sight if the spell says your target (be it point, unit etc) must be visible.

The base line I use is that Mystic Shield, Arcane Bolt and to unbind all state the target needs to be visible, as do the rules for picking a target for attacking.  Conversely, the rules for charging don't state anything about the target unit being visible - so you could charge round a corner to attack a hero who's hiding!

[Bohemond]

4 hours ago, RuneBrush said:

The way I've played it is that you only need line of sight if the spell says your target (be it point, unit etc) must be visible.

Thanks. Even though we are supposed to solve unclearities by simply talking to our opponent, it is good to know how others deal with the same issue. 

4 hours ago, RuneBrush said:

[...] you could charge round a corner to attack a hero who's hiding!

That idea never struck me for some reason!