kaerumata 蟇股

Frog-leg strut. A strut with legs spread like those of a frog. Kaerumata in the early Nara period developed from an inverted warizuka 割束 shaped strut to a very thick strut rounded on each end with an onion-shape carved halfway through, shizumibori 沈み彫. Frog-leg struts are usually positioned between parallel purlins *keta 桁 in the space between the bracket systems *tokyō 斗きょう that are atop each pillar. Frog-leg struts are also used to support transverse rainbow beams *kōryō 虹梁 that stretch across the core *moya 母屋 of a temple building or across the smaller transverse beams of the aisles *hisashi 廂. They are also frequently found in gable ends. The oldest frog-leg struts were shaped from single thick boards with no open spaces and were used to carry large bearing blocks and bracket arms *daito hijiki 大斗肘木 that in turn supported heavy beams *nuki 貫. This type of frog-leg strut is called itakaerumata 板蟇股. These solid board frog-leg struts were completely functional. The struts placed between two rainbow beams were wider than they were high. However, those positioned on beams to support the ridge were higher than their width. The use of solid-board frog-leg struts did not die out even though they were used less frequently from the Heian period through to the 13th century. From the 10th - 11th century, kaerumata began to have some open areas, and the timber used became thinner. Those with open spaces are called either honkaerumata 本蟇股 or *kurinuki kaerumata 刳抜蟇股. One method to shape the frog-leg strut was to use a single piece of wood and then cut openings to make a design. This is called *sukashi kaerumata 透蟇股. The shape of the openwork gradually changed. The legs became shorter, stretched out further, and the feet were elongated. Carvings gradually became more ornate in the latter Heian period and continued through the latter Kamakura period when intricate arabesques and even *hōju 宝珠 (treasure jewels) were included within the frame of the frog-legs. The inside decoration of frog-leg struts in the Nanbokuchō and the Muromachi periods became much more decorative and filled the entire space. Hōju, lotus, arabesques, flame patterns, peonies, paulownia, birds and clouds embellished the once simple frog-leg frame. During the Momoyama and Edo periods, the carvings within the frog's legs are often elaborate and many are brilliantly colored. Proportions of legs and feet changed and the bearing block on top of the frog-leg strut is often undersize. Some excellent work of sculpture filling the area between the frog-legs continued through most of the 17th century. The left and right pieces were carved out in reverse directions so that when combined a triangular shaped frog-leg strut was produced. This method was called the *gasshō 合掌 style. The upper part was curved to create a place for the insertion of the base of a bearing block *masu 斗. It is presumed from the paucity of examples that this technique never became popular. For a relatively short time a different process was devised to create decorative frog-leg struts: The strut was shaped and then cut in half vertically.