Look on the quest to see which area it is in (I think the first is in Haunted Cave for example) then go to that area. When in area, open map and you'll see the chest.
Also, FYI, in MB and Mooshu, you don't have to battle the enemies, just walk around the enemies over to chest. As long as you walk along the edge, they'll leave you alone and you can pick up your pieces.
Also, FYI, in MB and Mooshu, you don't have to battle the enemies, just walk around the enemies over to chest. As long as you walk along the edge, they'll leave you alone and you can pick up your pieces.