Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The soroban is an abacus developed in Japan. It is derived from the suanpan, imported from China to Japan around 1600. Like the suanpan, 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 beads: one bead having a value of five (called a heavenly bead) and four beads each having a value of one (called earth beads). Each set of beads of each rod is divided by a bar known as a reckoning bar. The number and size of beads in each rod make a standard-sized 13-rod soroban much less bulky than a standard-sized suanpan of similar expressive power. The number of rods in a soroban is always odd and never less than nine. Basic models usually have thirteen rods, but the number of rods on practical or standard models often increases to 21, 23, 27 or even 31, thus allowing calculation of more digits or representations of several different numbers at the same time. Each rod represents a digit, and a larger number of rods allows the representation of more digits, either in singular form or during operations.

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