A mixed wood bamboo and metal abacus, Suan Pan, the hardwood frame enclosing eleven bamboo and two metal rods holding separate registers of two and five huanghuali beads, the corners with cloud form metal mounts, 18.5 cm high, 37 cm wide, 2.8 cm deep. Other Notes: For performing basic addition, subtraction, multiplication and division, the suan pan, or calculating plate has been in use since the 15th century., Compare with a slightly smaller abacus from the Gangolf Geis Collection, sold Christie's, New York, 18 September 2003, lot 65