Chinese Suanpan counting frame with beads or Abacus, ca 19th

Chinese huanghuali wooden suanpan counting frame with beads|abacus, late 19th century to early 20th. The suanpan is a 2: 5 abacus: two heaven beads and five earth beads. An abacus (pl.: abaci or abacuses), also called a counting frame, is a hand-operated calculating tool which was used from ancient times in the ancient near east, europe, china, and russia, until the adoption of the arabic numeral system.[1] an abacus consists of a two-dimensional array of slidable beads (or similar objects). In their earliest designs, the beads could be loose on a flat surface or sliding in grooves. Later the beads were made to slide on rods and built into a frame, allowing faster manipulation. Each rod typically represents one digit of a multi-digit number laid out using a positional numeral system such as base ten (though some cultures used different numerical bases). Roman and east asian abacuses use a system resembling bi-quinary coded decimal, with a top deck (containing one or two beads) representing fives and a bottom deck (containing four or five beads) representing ones. Natural numbers are normally used, but some allow simple fractional components (e.g. 1⁄2, 1⁄4, and 1⁄12 in roman abacus), and a decimal point can be imagined for fixed-point arithmetic. Good vintage condition, some signs of wear consistent with age and use.