Bastion
马面
By Great Wall Archive · Updated June 2026
A bastion (马面) is a rectangular projection built out from the face of the Great Wall so that defenders standing on it could fire along the wall, not just outward from it. By covering the strip of ground at the foot of the rampart from the side, bastions removed the blind spot that an attacker would otherwise use to work right up against the wall.
Why a flat wall has a blind spot
Defenders on top of a straight wall can shoot at an enemy in front of them, but they cannot easily reach an enemy pressed against the wall directly below, where the parapet itself blocks the line of sight. That base of the wall is exactly where attackers want to be, to dig, scale, or shelter from missiles above.
A bastion solves this by sticking out past the wall face. From the side of the projection, defenders look back along the wall and cover the ground that the wall-top cannot — firing along the face, an arrangement later European fortification called enfilade.
Spacing and the bowshot rule
Because the protection depended on shooting along the wall, the projections had to be close enough together that their fields of fire overlapped. The rough rule was a bowshot apart, so that every stretch of curtain wall between two bastions stayed within range of archers on both. Closer spacing meant stronger cover; wider spacing left gaps an attacker could exploit.
A bastion (马面) is part of the wall itself, projecting from it, which distinguishes it from a watchtower (敌台) that rises as a chamber for shelter and storage. Many sections combine the two, with towers and bastions alternating along the line so the wall could both house its garrison and cover its own base.
Related
Sources
- Great Wall Archive — Data sources & methodology
- China's 2012 national Great Wall resource survey
Great Wall Archive. “Bastion (马面).” https://greatwallarchive.com/architecture/bastion