Is "see" the same thing as "line of sight?"

[Bareheaded Warrior]

To be honest I've tried so many different interpretations and house rules over the decades with different groups it would be hard to settle on one!

When I started with the 1st edition back in 1989 I went with interpretation 2, same as you, it was only about a year later when I was introduced to the 2nd edition that I realised that I may have been playing it wrong and started to use interpretation 1 but with the 2nd edition LOS rules. With my last gaming group I used 2nd edition LOS rules with interpretation 2 that I detailed on a different topic, but with my next group I'm planning on using interpretation 1 but without the "everything is visibile in the same room" rule, so more like the 1990 remake rules but with the 2 different LOS rules from the 2nd edition combined with my houserule around Sticky Combat.

Funnily enough none of these rulesets seem to make a huge difference to the game, at least in most scenarios in the official quests due to the placement of stuff in rooms (which may not be a coincidence) and the fact that you can see all of the smaller rooms and most of the larger rooms from the square outside the door anyway, but the game "system" encouraged players to create their own adventures from the very beginning, so we have to consider these. Interestingly in the 1st edition where if you use interpretation 1 in combination with the "can't step on the same square twice in the same turn" that can make quite a significant difference, in create your own quests, as it enables you to "hide" monsters out of sight, until a hero has stepped into the room and then they can't step back out until their next turn, but that rule was dropped in 2nd edition.

All of which brings me neatly onto ...

What changed in the 2nd edition?

The 2nd edition introduced a new variant of the line of sight rule, the original LOS rule remained in place for the purposes of visibility (missile attacks), a new variant LOS rule was introduced for the purposes of visibility (placement on the board) .

Neither of these rules appear to have superseded the "always having visibility within the same room" (both for missile attacks and placement) because that is still present in the rulebook.

All the other relevant text appears unchanged (I think but it is very hard to be sure!) so it initially appears that we still have the same dilemma in the 2nd edition that we had in the 1st...however if you consider the reasoning behind the introduction of this new LOS variant, which is irrelevant within the context of the same room, it is clearly relevant in the instance of what you can see in a passage, as it means that our "monsters in a line" scenario is now altered so that all the monsters are visible (placement) but only the first is visible (missile attacks), so they are all placed on the board.

The intent behind introducing this new rule reveals that interpretation #1 must have been the original intention, because if interpretation #2 was the original interpretation then rule (d) would mean all the monsters would be placed in the passage anyway, so there would be no need for this new rule to be introduced to lead to the monsters being placed, if they were already placed by rule (d).

[Onan]

The intent behind introducing this new rule reveals that interpretation #1 must have been the original intention, because if interpretation #2 was the original interpretation then rule (d) would mean all the monsters would be placed in the passage anyway, so there would be no need for this new rule to be introduced to lead to the monsters being placed, if they were already placed by rule (d).

I think the addition of this new rule was made by someone else than the original author of 1st edition rules. Maybe they found out that some people used the spell-casting visibility for placement and only revealed the first monster in a row. So they wanted to clarify that all monsters should be revealed. Whoever added this new rule didn't read the preceding paragraphs, because the rule contradicts the rule about opening doors.

I don't think a 2-stage reveal was the intention: a partial reveal when you open the door, then the full reveal when you step in. This makes things complicated for no benefit, and it is not in line with the reveal rules from the Genie spell and the alarm and secret door traps from the quests, where a new room is revealed no matter line of sight.

Also the 2-stage reveal would allow an exploit. I would call it the half-room-exploit. E.g. in The Trial, when the hero opens the door to Fellmarg's tomb, the mummy is not visible. The hero only enters when the skeletons are defeated, so that Morcar can't use the mummy while the skeletons are on the board.

[Bareheaded Warrior]

Just for clarity the additional rule under 2nd edition is

Deciding what can be seen by a player character is very important in determining what should be placed onto the board. Miniatures in the same room are always visible. Miniatures in passages or in different rooms are only visible if you can trace an unobstructed straight line between the two miniatures. If the line passes through a wall or a closed door then the miniature is not visible.

As far as I am aware (although I can’t be 100% certain) the same team produced both the 1st edition, 2nd edition and Kellar’s Keep and Return of the Witch Lord.
The above rule does contradict the door opening rule, as you state correctly, but then the rules in this space in the 1st edition already contain this contradiction, hence our earlier conversation about two different interpretations, the introduction of this new rule at the very least doesn’t make things worse than they were already.

On the other hand, your rule (d) above, to place all monsters on the board when you round a corner, not only does not appear anywhere in the rulebook, it also introduces a second contradiction with the Moving Around the Board rule as that states that when you round a corner you place visible monsters onto the board.

This additional rule in the 2nd edition does restate the principle that what can been seen determines what should be placed on the board.

The alarm from Rescue of Sir Ragnar, for example, is a quest specific exception to the general rules, revealing a new room when there is no character (hero) in the room or with line of sight into the room is clearly an exception to the general rules whichever interpretation you use.

The “exploit” that you mention may well have been intentional under the 1st edition, a character opening the door may only see “half the room” containing a lone Goblin, decide to continue his move by charging in and slaying it in a single mighty blow, only to discover once in the room, that there are two Chaos Warriors in the hidden “half of the room”, and he is trapped as he is unable to move back out of the room, as under the 1st edition rules, you cannot move through the same square twice on a single turn.

[Onan]

On the other hand, your rule (d) above, to place all monsters on the board when you round a corner, not only does not appear anywhere in the rulebook, it also introduces a second contradiction with the Moving Around the Board rule as that states that when you round a corner you place visible monsters onto the board.

With interpreatation2 of visible:

Interpretation 2) The 2nd rule defines what "visible" in the 1st rule means: anything "on the map in the Quest book (apart from traps and secret doors)"

With this interpretation the "Moving Around the Board" rule means that you place everything (apart from traps and secret doors), so it is covered by the rules and there is no contradiction.

This additional rule in the 2nd edition does restate the principle that what can been seen determines what should be placed on the board.

With interpretation 2 it doesn't restate anything, but introduces something new. With interpretation 1 it redefines visible: before it was like spell-casting, now without miniatures/models blocking LOS. In either case this new rule introduces a contradiction to the "Opening Doors" rule. So whoever added this rule didn't think it through.

As I said before about 2nd Edition:

Morcar has to resolve the contradiction by prioritizing either of the 2 rules:
Option 1) "opening doors" rules has higher priority: This means that when a Hero opens a door into a corridor, everything is revealed, but when he enters a corridor from a junction, only pieces with an unobstructed line are revealed. Since miniature do not block the line, it doesn't make any difference from a practical point of view. You could construct a conflicting situation by placing a monster behind a single blocked square inside a 2 square wide corridor, but this is rather theoretical.
Option 2) "what can be seen?" rule has higher priority: This means that when a hero opens a door, he would only have a 90 degree wide field of view into the new room or corridor. The sides would be blocked off by the wall edges around the open door. He would have to step into the room to see everything inside. This means that on Morcar's turn Morcar would not be allowed to move the miniatures inside the blind spot, since they are not yet on the board.

In 1st edition you have to choose between 2 interpretations of visible. In 2nd edition visible for placement is defined, so no interpretation is necessary. But since it introduces a contradiction you have to decide on 1 of the options above. Once again it is up to you to decide if you reveal the whole room at once or in 2 steps.

In 1st edition you have to interpret the rules, in 2nd edition you have to fix them. And I think this is not the only place where 2nd edition messed it up.

[Bareheaded Warrior]

Onan, can I just say that I appreciate your time and effort on this topic and apologies if at any point I come across as "narky", as you are aware I'm attempting to put together a "clarifications" document and the last thing I want to do is introduce "clarifications" that cause confusion or lead to a load more questions being asked as that kind of defeats the object of the article!

Moving Around the Board
As the characters explore Morcar’s dungeons, they enter new rooms and passages. If you are the first player to enter a new room or passageway, you should give the evil wizard player enough time to consult the Quest book and place onto the board any visible monsters and furniture.

Opening Doors
Characters and monsters can only enter and leave rooms through open doors. Monsters cannot open doors.
You can open a door by moving onto the square in front of it. You do not have to open a door if you do not want to. Opening a door does not count as a move.
As soon as a door is opened, the evil wizard player must place any pieces shown for that room or passage on the map in the Quest book (apart from traps and secret doors). Once opened, a door remains open for the rest of the game. The evil wizard player should remove the closed door piece and replace it with an open door.
Note that, because you may not move through the same square twice in one move, if you move through a door, you may not pass through it again until your next move.

Under the 1st edition, when you talk about the 2nd rule defining the meaning of the 1st, I just want to double check that I understand you correctly. What you are saying is that the "2nd rule" under Opening Doors where it states "As soon as a door is opened, the evil wizard player must place any pieces shown for that room or passage on the map in the Quest book (apart from traps and secret doors)" is intended to define what is meant by the word "visible" under the "1st rule", in the previous section under Moving Around the Board where it says "If you are the first player to enter a new room or passageway, you should give the evil wizard player enough time to consult the Quest book and place onto the board any visible monsters and furniture." (italics are mine)

If I am correct in stating your position, then I have a few last (possibly) questions...

Q1. The word "visible" under the Moving Around the Board section does not need defining at this point as it has already been defined earlier in the document on p10 under casting a spell. If you choose to use the wording in the Opening Doors section to (re)define the meaning of the word "visible" under the Moving Around the Board section then you are creating a contradiction within the rules by defining the same word in two different ways.

I think that your statement that the rules around visibility in the casting a spell section only apply to spells and missile attacks and NOT to visibility in terms of placement, is just an assumption that you have made to avoid a contradiction caused by your own interpretation.

If the rules around visibility in the casting a spell section only apply to spells and missile attacks and NOT to visibility in terms of placement, then your statement that "when the hero enters a new passage from another passage the evil wizard player must place any pieces shown for that passage on the map in the Quest book onto the board (apart from traps and secret doors)" directly contradicts the statement in the rulebook "If you are the first player to enter a new room or passageway, you should give the evil wizard player enough time to consult the Quest book and place onto the board any visible monsters and furniture" again the italics I have added.

Please explain why you think this contradiction between your interpretation and the stated rules applied when moving from passage to passage can be resolved by applying the rule about opening doors when there are no doors to open when moving from passage to passage?

Q2. The "2nd rule" under Opening Doors where it states "As soon as a door is opened, the evil wizard player must place any pieces shown for that room or passage on the map in the Quest book (apart from traps and secret doors)" is clearly an instruction to the evil wizard player of what to do as soon as a door is opened which takes place BEFORE the first player enters the room (in fact they may choose to never enter this room) whereas the "1st rule" under the Moving Around the Board where it says "If you are the first player to enter a new room or passageway, you should give the evil wizard player enough time to consult the Quest book and place onto the board any visible monsters and furniture" is clearly an instruction to the first player (and indirectly to the evil wizard player) of what to do when the first player enters a new room which takes place AFTER the door has already been opened.

Please can you explain why would you ever need to allow the evil wizard player enough time to consult the Quest book and place onto the board any visible monsters and furniture when the first player (character) enters a new room, if the only way they can enter a room is by opening the door first, and opening the door already results in the evil wizard player placing any pieces shown for that room on the map onto the board (apart from traps and secret doors). Why would the evil wizard player ever have to place all the monsters and furniture again?

Q3. If the two-stage reveal of the room that happens first when you open the door and second when you step into the room was NOT intentional, then what possible reason is there to not only include the rule about "not being able to move through the same square twice in one move" in the rulebook, but to repeat it a second time in this same section? Surely the potential for a player to choose to act on the partial information revealed and move through the door into the room, thus revealing any "hidden" monsters, regret his decision but be unable to move back out of the door until his next move, is exactly why this rule is repeated in this very section?

[Onan]

No problem, BHW. I enjoy the discussion and I really want to understand why people apply the 2-stage reveal. I really like your rule clarification document and many things about HQ gold.

Q2 is a valid point. I have always wondered why you should give the EWP time to place things when the hero enters a room. Normally the room would already be placed when the door is opened (except for teleporters and pass-through-rock). With the 2-stage reveal this rule would apply regularly.

Q3 is also very good. With the 2-stage reveal the rule about no backtracing would make a difference.

In Q1 you also make a very good point: In 1st edition "visible" is first used before the "Moving around the Board" chapter, because the way of the wizard comes before the way of the scout. In 2nd edition "visible" is first used in "Moving around the Board", because they put spell casting to a later point. So the reason for adding the "What can be seen" rule might be that "visible" was not defined before.

I think that your statement that the rules around visibility in the casting a spell section only apply to spells and missile attacks and NOT to visibility in terms of placement, is just an assumption that you have made to avoid a contradiction caused by your own interpretation.

Just like your assumption that they forgot to add "visible" in the "opening doors" rule.

I can't answer Q2 and Q3, only speculate. I think they wanted entering a room to be commital. Maybe at an early stage of the rules there was no "Opening Doors" while standing still option, but you just stepped into the room, thereby opening the door. That's how children often play it. They place the hero inside the room, then give me the closed door they just jumped, and I say "wait, give me time to set up the room". But this is just a guess.

I will try to explain how I get to my interpretation of Q1:

The numbering of the rules is getting complicated, so let's call the rules like their chapters (all 1st edition, except for "what can be seen"):

Casting Spells rule:

Models in the same room as the spell-caster are always visible. Models in passages or in different rooms are only visible if you can trace an unobstructed straight line from the spell-caster to the target. If the line passes through another model, through a wall, or through a closed door, then the target model is not visible.

Moving Around the Board rule:

If you are the first player to enter a new room or passageway, you should give the evil wizard player enough time to consult the Quest book and place onto the board any visible monsters and furniture.

Opening Doors rule

As soon as a door is opened, the evil wizard player must place any pieces shown for that room or passage on the map in the Quest book (apart from traps and secret doors).

What can be seen rule:

Deciding what can be seen by a player character is very important in determining what should be placed onto the board. Miniatures in the same room are always visible. Miniatures in passages or in different rooms are only visible if you can trace an unobstructed straight line between the two miniatures. If the line passes through a wall or a closed door then the miniature is not visible.

Let's say Onan playing 1st edition comes across the word "visible" in "Moving Around the Board". Let's say Onan doesn't remember that the word visible was used before in "Casting Spells". Onan reads the next sentence about "Opening Doors" and sees that not everything is placed on the board: There are secret things that are not placed. So Onan thinks maybe visible means the opposite of secret (hidden).

With this in mind Onan can handle the following situations:
- a hero opens a door into a room or passage: Apply "Opening Doors" rule and reveal everything not secret.
- a hero steps from a corridor into another corridor: Apply "Moving Around the Board" and reveal everything visible.

Onan would expect the 2 situations to be handled in the same way, so he is happy thinking that visible in "Moving Around the Board" means the same as "not secret". So he always places everything not secret and is happy that the 2 rules match. Maybe he wonders how a hero would enter a room that was not already revealed, but soon he forgets about it.


Let's say BHW playing 1st edition comes across the word "visible" in "Moving Around the Board". Let's say BHW remembers that the word visible was used before in "Casting Spells". So he applies "visible" from "Casting spells" to "Moving Around the Board".

With this in mind BHW can handle the following situations:
- a hero opens a door into a room or passage: Apply "Opening Doors" rule and reveal everything not secret.
- a hero steps from a corridor into another corridor: Apply "Moving Around the Board" and reveal everything visible as defined in "Casting Spells".

BHW would expect the 2 situations to be handled in the same way, so he is confused that they are handled differently. He thinks that maybe they forgot the word "visible" in "Moving Around the Board", and he uses "Casting Spells" visibility for "Opening Doors", too.

Now Onan switches to 2nd Edition. He reads the additional "What can be seen" chapter and is confused. He wonders if he played the game wrong all the time.
What has changed?
- a hero opens a door into a room or passage: Same as in 1st edition, apply "Opening Doors" rule and reveal everything not secret.
- a hero steps from a corridor into another corridor: Apply "Moving Around the Board" and only reveal things with an unobstructed line (models/miniatures don't obstruct).

Ok no problem, the hero is already inside the corridor, so everything inside the corridor up to any Blocked Square is visible. Again Onan reveals the complete corridor.

Onan doesn't understand why they added the rule, but he is happy thinking his way of playing is conformant to the new rule.


Now BHW switches to 2nd edition. He reads the additional "What can be seen" chapter and is happy. Models hiding behind other models have always been a pain to handle. Now models don't count to "Moving Around the Board" visibility anymore because of the new "What can be seen" visibility rule. But hey, they still forgot to mention "visible" in "Opening Doors".

BHW doesn't understand why forgot to fix it. But he is happy thinking that "Casting Spells" visibility was meant for "Moving Around the Board", and it has now been refined.

[Bareheaded Warrior]

Where there is doubt (and it is fair to say 12 pages into the debate, that there is doubt ) I generally prefer the simpler implementation or change.

Interpretation #1: The Opening Doors section is missing the word "Visible"

If you consider our interpretation 1, then in the 2nd edition you have just two rules, one that covers visibility in terms of both placement and missile attacks when you are in the same room, and a second that covers when you are NOT in the same room, that has two parts, one for placement and one for missile attacks.
In terms of tweaks, you only have to insert one single word for clarity the word “visible” into one section of the text (actually one section in 1st edition, two sections in 2nd edition)

Two rules, one tweak, seems relatively simple to me.

Interpretation #2: The Opening Doors section is correct as written

If you consider our interpretation 2, then in the 2nd edition you have the same two rules as above, but there is an additional rule, the special circumstance around opening doors:

“As soon as a door is opened, the evil wizard player must place onto the board any pieces shown for that room, or passageway, on the map in the Quest Book.”

So, three rules rather than two (and two rules are generally, all other things being equal, simpler than 3) but in terms of changes this is where things start to get more complicated…

Case 1 What can the Wizard see.png

The Wizard opens the door and as soon as a door is opened, the evil wizard player must place onto the board any pieces shown for that passageway on the map in the Quest Book, but which of the monsters must he place onto the board?

The Wizard is not in the passage, he is still in the room, so which passage is the one being referred to, is it the one that runs horizontal to the doorway, so he should place the Orc only, but does the presence of the Blocked Square tile mean that the bit of passage that the Orc is in isn’t part of the passage that is being referred to, quite possibly but nowhere in the rulebook does it state that, so you would have to make a change to clarify, but what about the Goblin, is he in the passage that the Wizard has opened the door onto, he is if you classify all these joined up bits of passages into one, but not if you don’t. Same for the Fimir. In fact, in the rulebook, whilst rooms are defined in such a way that makes it clear and simple to determine the boundary of a room and therefore where room A begins and ends and where room B begins and ends, the same is NOT the case for passages. Passages are effectively defined as “not rooms” but nowhere does it define in the rulebook where one passage ends and another begins, under interpretation 1 it doesn’t need to, because all that matters is whether I can or cannot see the monster, under interpretation 2 however it is a hole that needs to be filled

So, interpretation 2 has three rules instead of just two and on top of that additional work is needed to clarify passages as opposed to just inserting a missing word, so I think I’ll go with the simpler option of interpretation 1.

As an aside, since I posted earlier the bit around monsters hiding in a room out of sight in the corners so that they can lure you in and trap you and I stated that when the 2nd edition scrapped the restriction on moving through the same square twice then this “trap” no longer applied, it has been pointed out to me that this isn’t strictly speaking correct. In the 2nd edition if you move into a room revealing previously hidden monsters, this “trap” still applies if you move into the room using your last point of movement or if the room contains a trap behind the door which ends your turn and even if neither of those scenario occur, the act of stepping into and then out of the room consumes two extra points of movement, which may well make the difference between the pursuing monsters being able to catch you and attack in the same turn, or not.

[Onan]

As a backup of your interpretation, I have found that in the German 2nd Edition the translator added the word "visible" to the "Opening Doors" rules. So you're not the only one who reads the rule this way.

As a backup for my interpretation, line of sight was removed for placement in the new "First Light" rules:

• When a hero looks down a corridor, place any doors, blocked-square tiles or monsters according to the map.
• Blocked-square tiles show where extra walls have been built. Neither heroes nor monsters can move through blocked-square tiles.
• When a hero opens a door, place any monsters, treasure chests, and any other items that belong in that room.

So I'm not the only one who doesn't want to track lines between models.

The situation in your diagram is a corner case. I would reveal none of the monsters when the opens the door. I would reveal none of the monsters when the steps out of the door. As a house rule, I allow heroes to peak around the corner, so I would reveal the when they ask me to reveal the corridor. But in first place I would not place the there when designing a quest

The blocked squares are not covered by "Opening Doors", but they are defined as walls. So I would say that behind the blocked square there is another corridor, and I would not reveal it. If you use line of sight, this doesn't save you from the missing definition of corridor boundaries: You still have to decide if the hero can search on either side of the blocked square or only once.

Maybe I would add to my interpretation of 1st edition placement visibility: everything not secret and not behind a blocked square. This would explain the use of visible in the context of searching in 1st edition:

Characters may not search if they are next to a monster or if there is a monster in the same room or visible in a passage.

In 2nd edition this was changed to:

Characters may not search if they are adjacent to a monster or if there is a monster in the same room or passage.

So in your example you would not know if the wizard can search the passage if there is an Orc behind the blocked square when using 2nd edition.

I wouldn't consider it a simplification if you have 1 rule that covers 2 aspects and says: depending on the aspect you do either this or that (in this case "miniatures block LOS if spell or missile else not"). I would rather have 2 seperate rules. Also in the 2nd edition rulebook they are not one rule for 2 aspects, but 2 rules in different chapters.

But I would consider a simplification if I did not have to draw an invisible line, but could just work with areas. So I don't do partial reveals. If I want an ambush of an unseen monster when the heroes enter a room I would use a secret door that the EWP can open.

By the way, how could they mess up placement visibility rules AGAIN in First Light Opening a door into a room is defined, but not opening a door into a corridor. Looking down a corridor is not defined. So my guess is when you open a door into a corridor you look down the corridor from behind the door. And if you step next to a junction you look down the new corridor from your current corridor.

[Bareheaded Warrior]

As a backup of your interpretation, I have found that in the German 2nd Edition the translator added the word "visible" to the "Opening Doors" rules. So you're not the only one who reads the rule this way. As a backup for my interpretation, line of sight was removed for placement in the new "First Light" rules.

I think that the key difference here is that the German 2nd edition translation dates back to the period in question whereas "First Light" was published some three decades later. I'm sure that there is a principle about evidence being more valuable if it was closer to the period in question, and there is definitely a principle of assigning more value to information that supports my own point of view

My reasons for giving the example that I did in my last post wasn't so much to understand how you would handle it, although that is always interesting, it was more to demonstrate that your interpretation would lead to more changes being needed, so is less simple to implement. This doesn't mean necessarily that it is wrong, or bad, just that it isn't the best interpretation for a clarification document.

I have many house rules in play at my table which I believe improve the game, others may not share that belief, but I've avoided including them in my clarification document because they are additional, extra improvements or enhancements but are NOT clarifications of the official rules, they are something more (although it many cases it is a grey area between clarification and enhancement!)

If you use line of sight, this doesn't save you from the missing definition of corridor boundaries: You still have to decide if the hero can search on either side of the blocked square or only once.

Again this appears to be an attempt to clarify or simplify in the second edition, but actually achieves the opposite result, but I'll make sure to include that in the clarifications document as the 1st edition wording is clearer and simpler in this example than the 2nd edition (and sadly there are quite a few examples of these types of changes, I seem to discover more and more with every passing year, so perhaps there was something to your earlier statement around a change in personnel, or at least key personnel, between the 1st and 2nd editions)

I wouldn't consider it a simplification if you have 1 rule that covers 2 aspects and says: depending on the aspect you do either this or that (in this case "miniatures block LOS if spell or missile else not"). I would rather have 2 seperate rules. Also in the 2nd edition rulebook they are not one rule for 2 aspects, but 2 rules in different chapters.

Fair point, I should consider the second edition to have three rules rather than two, but it doesn't change the fact that your interpretation adds an extra rule on top of the THREE rules under my interpretation.

But I would consider a simplification if I did not have to draw an invisible line, but could just work with areas.

Yes but for me it isn't about creating the simplest ruleset (that falls under the remit of house rules), it is about finding the simplest valid interpretation of the existing rules.

I agree entirely that it is annoying when areas of the rules are consistently messed up, I understand that it is very difficult when making changes to rules, to foresee or even test for all the unintended consequences, but when it is a case of the rules being fine, just the wording that is in need of some clarification, it should only need a tweak, the odd word or two added, rather than re-inventing the wheel, by introducing changes that aren't needed, and any unintended consequences that inevitably follow (like the disarming trap rules discussed here) hence my desire to create a clarification document for the classic edition of the game, clarifying the wording of the rules where needed (or choosing whichever is the clearest from either 1st or 2nd edition) without trying to change the mechanics of the rules themselves.

[Parzival]

As an insight to the current rule interpretation, let’s have a look at how the Companion App handles things:

When a hero reaches the penultimate square of a corner in a corridor, the square just around the actual corner becomes visible, and any block, door or monster on that square is revealed. When the hero advances to the square at the corner itself, he can see down the entire length of the corridor, and all blocks, doors, and monsters in that straight line of vision are revealed without regard to LOS rules.

When a door is opened, everything in the room is revealed (other than traps or secret doors, and special “hidden” monsters— as a mummy inside a sarcophagus). Again, any LOS is ignored. (This makes sense, as placing these elements for the hero opening the door inherently reveals their existence and position to the rest of the party outside the door, no matter where the other heroes are! So it’s not so much “sight” as “reported and believed” that matters here.)

If the heroes move out of LOS of the enemy, it doesn’t disappear, but its position is known as it moves, so long as it moves in areas already having been seen by at least one hero. I seem to recall in a few instances the AI Zargon moving a monster into an unrevealed corridor, with the monster thus disappearing into the “fog of war” covering unrevealed areas. This of course really isn’t possible with a tabletop situation, so presumably the party gets to “know” of the monster’s movements even if they haven’t yet seen the corridors it moves along.

So we can see that what can be “seen” and what is within LOS of a particular hero/monster are different considerations.

Also, it should be noted that LOS does not block the function of searching for traps or searching for secret doors in either a room or a corridor— it doesn’t matter if the Wizard is completely boxed into a corner by his three allies, he can still search for secret doors or traps unimpeded. But notice that also, if a hero is in a room which contains no monsters, if he is out of LOS of any monster in an adjacent room or corridor, he can still search the room he is in for anything— including treasure! However, if a monster has LOS on him (and therefore vice versa) then he can’t do so, even if that LOS is technically blocked by another hero.

And of course if a hero moves out of sight or LOS of a monster, the monster doesn’t vanish from knowledge of its location, movements or actions, even if no heroes at all are in LOS of it.

So sight is a fairly broad interpretation in some instances (revealing what is there) but very specific in others (searching a room or corridor).

I will note that the Companion App is a bit weak on handling LOS with regards to magic— I have had it declare that “no target is in sight” even for figures in the same room as the Wizard and diagonal to that Wizard with no blocking elements in between at all! Though interestingly, that mostly applies to “dual use” spells like Genie which either opens a door OR attacks a selected target “in sight” with 5 dice. The App doesn’t handle the latter issue at all, but only gives the option of opening a door OR cancelling the spell. So you just have to ignore the App, and apply the Genie’s attacks without bothering to go through the “Cast a spell” function. [EDIT] It’s also unclear whether certain beneficial spells on party members require LOS or just being “in sight”— that is, present in the same corridor or room. The App does not handle these spells, either.

It’s also unclear what LOS means with regard to looking around a corner in a corridor— can a hero with the crossbow shoot a monster in a corridor from just around a corner? Like a pop shot as one might see in an action movie— lean out, shoot, jump back? My interpretation would be that he has to step fully into the “new” corridor in keeping with LOS, to shoot an enemy further away than just around the corner…

EDIT: Forgot to mention that if a monster is in a chamber with a hero, it doesn’t matter if the monster has LOS to the hero (or vice versa), the App will not let the hero search the chamber for anything. So in the example previously posted of the dwarf blocked from LOS of the monsters, in the App he would not be able to search for the pit traps on his side of the room.
Part of this should be considered in light of the rule that any search applies to an entire room, not just the portion of it which is visible to the hero. So in this instance, the monsters can be “seen” but not attacked by the dwarf, and vice versa.
Visually, I imagine this as being a situation where yes, you can see that there’s some big hulking brute (or cackling little twerp) on the other side of the Barbarian from you, but you’ve got no clear path to shoot or strike it without hitting your buddy. So you can see it (or a portion of it), you just can’t see it well enough to attack it.