The problem with this is that we need a die roll that matches the number of rooms in the dungeon... and we might not know how many rooms the dungeon has yet. Instead of rolling directly for the room number, then, we could instead roll for the relative room number. We could roll a d10 on the following table:
|Roll||Room #|||||Roll||Room #|
|1||Current Room - 4|||||6||Current Room + 1|
|2||Current Room - 3|||||7||Current Room + 2|
|3||Current Room - 2|||||8||Current Room + 3|
|4||Current Room - 1|||||9||Current Room + 4|
|5||Back to Current Room|||||0||To Distant Room, Same Direction|
In other words, subtract 5 from the current room number, then add the result of a d10 to get the destination room number. This means that most corridors will lead to nearby rooms: rooms you have just drawn, or rooms you are about to draw.
If the result is less than 5, it's one of the previous four rooms you've drawn. Draw your corridor as straight as possible towards that room. You might have to make one or two turns, if the corridor starts in the opposite direction (the way Room 1 in the example picture above is west of the door in Room A, so the corridor must make a U-Turn to connect.) You can still use the random corridor shape tables from whatever generator you are using to test the corridor every 60 feet or so for side passages or doors.
If the result is 5, the corridor re-connects with the room it leaves. Either there are two doors in the room and the corridor connects them, or the corridor splits into a Y or T and forms a loop that way. Again, check every 60 feet, or possibly even every 30 feet, for doors or branches off the main corridor.
If the result is more than 5, the corridor leads to a new room. assuming you haven't drawn those rooms yet. The general direction of the room is the general direction the initial door or doorway is facing. You can use the standard tables from whatever generation system you are using to test the corridor every 60 feet for turns or side passages, or you can roll a d10 for corridor length:
- on a 0, there is no corridor and the door leads directly into the new room;
- on a 1-6, multiply the result by 10 for the length of the corridor;
- on a 7+, draw 60 feet of corridor and then test for turns, doors, or side passages.
For the first five rooms of a map, use the results as the raw room number. If a corridor has to cross other corridors or rooms to reach its destination, roll on the following table:
|1-4||corridor runs under area|
|5||secret door connects to area|
|6-9||corridor runs above area|
|0||dead end, no connection|
If the corridor runs under or above the area, there will be stairs just before it crosses the area, and stairs on the other side. Optionally, there are stairs on even rolls and ladders on odd rolls.
If the corridor ends, either with a secret door or a true dead end, there is no need to worry about finishing the connection on the other side of the already-mapped area.