Unshu, Kamedake Soroban. The soroban (counting tray) is an abacus board developed in Japan. The soroban is still used today, despite the proliferation of practical and affordable pocket electronic calculators.
The soroban is composed of an odd number of columns or rods, each having five beads: one bead valuing at five (called a heavenly bead) and four beads valuing at one (called an earth bead). Each set of beads of each rod is divided by a bar known as a reckoning bar. The number of rods in a soroban is always odd and never less than nine. Each rod represents a digit, and a larger number of rods allows the representation of more digits, either in singular form or during operations.
The beads and rods are made of a variety of different materials. Most soroban made in Japan are made of wood and have wood, metal, rattan, or bamboo rods for the beads to slide on. The beads themselves are usually biconal (shaped like a double-cone). They are normally made of wood (boxwood or birch), although the beads of some soroban, especially those made outside Japan, can be marble, stone, or even plastic. The cost of a soroban can increase depending on the materials. Our e-mail address is: email@example.com