17.1: A crag represents rough terrain strewn with boulders, crevices, and the debris of numerous rock slides. Any hex containing four gray, irregular boulder symbols-such as 15X9 or 9H8 - is a crag hex. It is not the boulder symbol itself, but rather the entire crag hex (inclusive of hexsides) which affects any LOS drawn into or through it.
17.2: A crag is not a LOS obstacle, but it does Hinder same-level LOS by adding a +1 Hindrance DRM for every crag hex [EXC: A6.7] between the firer and target.
17.3: A crag hex has a TEM of +1 to any fire traced into it.
17.4: It costs Infantry two MF and Cavalry/
17.5: Fortifications other than Wire are not allowed in a crag hex.