Treasure Chests are a gameplay element from Alex Kidd in the Enchanted Castle and Alex Kidd in Shinobi World.
In Alex Kidd in the Enchanted Castle, red treasures chests are common and contain Baums, either as four coins (10 Baums each) or as a bag (100 Baums). Black treasure chests may contain an 1UP, an Amulet, or four bombs.
In Alex Kidd in Shinobi World, treasure chests may contain a Heart, Darts, Power, Ninja's Crystal Ball, or Alex Doll.