Definition of the Bunker
Bunker is one of the five defined areas of the course. The official definition states that bunkers are “specially prepared areas of sand, which is often hollows from which turf or soil was removed”. These hollows can be filled with sand or a similar material comprised of very fine particles, as well as any mixture of sand and soil.
Bunkers can be located anywhere on the hole, near or in fairways (fairway bunkers) or close to putting greens (greenside bunkers). There are no formal restrictions on their size or depth. See examples on pictures below.
There are also some areas similar to bunkers, called waste bunkers or waste areas. They can be filled with similar material and are similar in shape to normal bunkers. They are not specially prepared, remain generally unmaintained and do not have a rake. Under Rules of Golf waste bunkers are not bunkers nor penalty areas, but they are the part of general area.
A Committee and golf courses can declare any area of sand as part of the general area (not a bunker). They can also declare a non-prepared area of sand as a bunker. Such decisions are always included and described in local rules.
When a ball is in the Bunker?
A ball is in the bunker when any part of the ball touches sand on the ground inside the edge of the bunker, or ball is inside the edge of the bunker.
A lip, wall or face at the edge of a bunker and consisting of soil, grass, stacked turf or other artificial materials is not a part of bunker.
When a ball lies on the boundary between the penalty area and the bunker the ball is in the penalty area if “any part of it lies on or touches the ground or anything else inside the edge of the penalty area is above the edge or any other part of the penalty area“. If the ball doesn’t lie on or touch the penalty area it is in the bunker. See the picture below – the boundary edge between the bunker and the penalty area is marked by black dashed line.
update: March 2021