Crown green bowls is played on a specially prepared short-cut smooth grass surface known as a bowling green or simply the green (usually 45×45 yards). The green usually has a raised centre known as the crown which can often be as high as 30 centimetres above the edge of the green. The green has a ditch around the edge, and slopes on all sides from the crown towards the ditch. Greens are usually rectangular or square, but L-shaped and circular greens also exist. The surfaces also often feature ridges, hollows and slopes to make the game more difficult. Due to this vast array of historical differences, no rules stipulating the shape, size or height of the crown are laid down by the British Crown Green Bowls Association.
Philip Wright Crown Green Bowling Academy 