This is a novel abacus with two beams to divide the rectangle into three decks. There are still five beads in the middle deck, but there are two beads each in the upper and bottom deck. This kind of abaci usually has many rods, for example, 21 or 13 ones. This is determined by their unique function, which is to enable two people to use one abacus when the size of the accountants’ table is limited. With the bi-directional abacus, two accountants can stand on both sides of the counter; each with two beads plus five beads.
Later on, as the technology of reckoning develops, the bi-directional abacus is cleverly used to do calculations concerning negative numbers, thus its connotation is deepened.
The Abacus which Has Nine Levels
This is a big, wooden set of abaci with a length of 60 cm and a width of 40 cm. On each of the 9 levels, there is an abacus of 24 rods, so the total amount of beads is as many as 1512. Made to meet the needs of the successful businessmen of Anhui Province, the big set is often seen put on the table of the general accountant, who will do the accounting of each department on different levels, and generalize the result on the bottom abacus. In this way, the daily, monthly or annual business picture can be understood fully at one glance. This abacus performed functions just like a modern computer. “The Chinese invented the computer long time ago. That is the nationally used calculator—abacus,” said Dr. Li Zhengdao to then-Premier Zhou Enlai in October, 1972.
The Abacus Inlaid in a Scratching Tool
Made in the Qing Dynasty, this is a work of art made of bamboo with beautiful carvings. A scratching tool is a common and interesting tool in every household. With this, one can scratch his itchy place (especially in a place hard to reach by oneself, such as one’s back) easily. But in this scratching tool, a delicate abacus is built inside. The whole tool is carved from one piece of bamboo, and so is the abacus, which we know because there is no trace of its assembly. It is even more ingenious of the craftsman that he has made all the little beads into regular round shapes and they are easy to move up and down. As an amalgamation of art and practical function, this piece of work is a jewel of artistic design.