A hard block (ハードブロック Hādoburokku) is a core gameplay element in most Bomberman games. Any wall that cannot be destroyed by a bomb blast is considered a hard block. Hard blocks are typically immobile, though special types of indestructible walls, such as the revolving door, can be moved. Hard blocks define the shape of a stage, providing a boundary and maze-like grid for the player to explore.
The term "hard block" appears to have been first used in the Super Bomberman 2 Hudson Official Guidebook. Prior to that publication, the term indestructible block (破壊不可能 hakai fukanō) was commonly used. In the original Bomberman for the NES/Famicom, hard blocks were simply referred to as concrete (コンクリート konkurīto).