Germanic castles of the Holy Roman Empire had lower and upper valleys – called Vorbug and Kernburg respectively. Many German0speaking countries had castles with double curtain walls and narrowed enclosures between them. These zwinger were used as a killing ground.
In Medieval Britain, the most important buildings such as the keep were located inside the inner bailey of the castle – sometimes called the central bailey. There are, however, exceptions. Flint Castle has its keep on the outside. More frequently than not, however, outer baileys or yards held less important structures such as stables.
Some outer yards were mostly defensive in function and had no buildings. Like the mentioned Germanic examples, they mostly were narrow passages between concentric enceintes.