I've been looking through my rulebook a few times now to see if there is any mention since there are some that dont have a castle space with a 6 on them.
Rulebook, page 12:
Players are free to choose which side (front or back) of the board they wish to use, as well as which (dark green) space they will place their starting castle on.
Also I was wondering if anyone could tell me whats with the 3 castle space on the main board near the 6 depot? It has ABCDE on either side of it and in different colors. I saw no mention of it in the rule book.
Rulebook, bottom of page 3:
Note: In the three-player game only, there is an exception for the dark green space in the No. 6 depot: In phases A, C and E a castle is placed onto it as normal, but in phases B and D a mine (grey) is placed there instead!