Orin
bowls (bells) have been made in Japan since the 500s, when the methodology came from China. They are cast as a mixture of molten bronze and tin are poured into clay molds, which give shape to both the inner and outer bell. This alloy results in a durable bell with a beautiful sound. Bronze is a soft metal and tin is hard. The hardness of the bell can vary depending on the percentage of the two metals in the blend. The harder the bell, the clearer the sound and the longer the reverberation.
Traditional handmade molds are made by combining sand, clay, and rice husks, resulting in a somewhat porous mold with good airflow that avoids shape and sound-distoring gasses that may become trapped. The molds are then fired in a ceramics kiln.
The combination copper and tin alloy is heated to 1300 degrees C. before being poured into the pre-fired molds.
After cooling, the orin are removed by breaking up the clay molds. Then, each bowl is individually and precisely hand-shaped by carving and polished using a lathe. Craftspeople are careful to minimize the amount of carving so as not to diminish the sound of the bell. Furthermore, attention is paid to monitoring weather conditions and humidity, which can negatively influence the quality of sound.