the walls and to stop them from climbing the castle, including pots of hot sand, gun emplacements, and arrow slits from which defenders could fire at attackers while still enjoying nearly full cover. Spaces in the walls for firing from were called sama; arrow slits were called yasama, gun emplacements tepposama and the rarer, later spaces for cannon were known as taihosama. Unlike in European castles, which had walkways built into the walls, in Japanese castles, the walls' timbers would be left sticking inwards, and planks would simply be placed over them to provide a surface for archers or gunners to stand on. This standing space was often called the ishi uchi tana or "stone throwing shelf". Other tactics to hinder attackers' approaches to the walls included caltrops, bamboo spikes planted into the ground at a diagonal, or the use of felled trees, their branches facing outwards and presenting an obstacle to an approaching army (abatis). Many castles also had trapdoors built into their towers, and some even suspended logs from ropes, to drop on attackers. The Anō family from Ōmi Province were the foremost castle architects in the late 16th century, and were renowned for building the 45-degree stone bases, which began to be used for keeps, gatehouses, and corner towers, not just for the castle mound as a whole. Japanese castles, like their European cousins, featured massive stone walls and large moats. However, walls were restricted to the castle compound itself; they were never extended around a jōkamachi (castle town), and only very rarely were built along borders. This comes from Japan's long history of not fearing invasion, and stands in stark contrast to philosophies of defensive architecture in Europe, China, and many other parts of the world. Even within the walls, a very different architectural style and philosophy applied, as compared to the corresponding European examples. A number of tile-roofed buildings, constructed from plaster over skeletons of wooden beams, lay within the walls, and in later castles, some of these structures would be placed atop smaller stone-covered mounds. These wooden structures were surprisingly fireproof, as a result of the plaster used on the walls. Sometimes a small portion of a building would be constructed of stone, providing a space to store and contain gunpowder. Though the area inside the walls could be quite large, it did not encompass fields or peasants' homes, and the vast majority of