Minecraft wiki entry for Chest, associated text: A chest cannot be opened if there is an opaque block above it (in Bedrock Edition, bottom-half slabs prevent chests from being opened). Solid faces do not prevent chests from opening, so the lid of the chest can phase through blocks such as bottom-half slabs, stairs, and transparent full cubes such as glass and ice. Ocelots and cats sitting on chests prevent them from opening. Because chests themselves are functionally transparent, two chests can be stacked on top of one another while still allowing the lower chest to be opened. Players can open chests when players are being hurt (effect of instant damage, poison, wither, fatal poison or on fire) or hurt by anyone (players, zombies, skeletons, etc.).