THERE are many kinds of Bridges for spanning streams, or for reaching islands garden lakes. Some are of stone, some of wood, and others of wattle-work covered with earth. The Stone Bridges are often formed of a single rough slab of some kind of schist, or more generally, of a fine piece of wrought granite slightly arched. Where very large spans occur, two parallel blocks may be used, overlapping in the centre of the stream, and supported upon a trestle-like construction. An example of a monolithic Stone Bridge may be seen in Fig. 24, illustrating a small garden at Kamakura, called the Sho-fu-tei. Constructions of this kind are only used in level situations. Elaborate Stone Bridges formed of several spans of stone, supported upon intermediate granite piles, are used in important gardens, provided with moulded or carved parapets and posts. The manner of fitting partakes of the character of carpentry, even the large stone piles and newels being scarfed together like timber, and tenons and mortises being frequently employed. Arched Stone Bridges are found in some gardens, notably in the Koraku-En at Koishi-kawa (see page 31). This particular form is of Chinese origin, and is supposed to suggest the full moon, the semi-circular arch combined with its reflection in the stream below making a complete circle. The quick curve of its roadway, which corresponds almost with the extrados of the arch, necessitates the floor of the bridge being stepped.
