A shachihoko is an imagination animal with dragon (or tiger) head and the fish body. The figure of shachihoko was transmitted from China in Kamakura period with the architectural style karayo, and the wooden ones were used on the top of the roof of zushi (a miniature of Buddhist architecture to enshrine a Buddhist image). Oda Nobunaga used shachihoko made of tile to the buildings of a castle for the first time in Aduchi in 1576.
By the way, a pair of shachihoko that were not broken were excavated from the well of the Hiroshima castle in December, 2008. They were pasted with gold foil on eyes, ears, fangs, fins and so on. It is thought from the whole shape and the details that they were produced at the end of the 16th century. They are valuable to know the initial shape of shachihoko, because they are the oldest shachihoko in almost complete shape.
In addition, they are valuable as the standard to identify of the part and presume at the age, when splinters of tile are excavated.