The chamber of secrets

[Sam Riddle]

If Fred and George had the map before Harry, wouldn't it have shown where the C of S was?

[Scellanis]

the map was made by the marauders (James Potter and co) and until Harry found the chamber the only people who knew where it was where Tom Riddle and Salazar Slytherin since you need to be a parseltongue to get into it

since i think the map was made from their experiences of exploring the castle (thats how it seems cos they know the castle on the map off by heart) then the chamber wouldnt appear on the map cos they wouldn't have known where it was

[werebane]

yea, they wouldnt know where the thing was