3 3/4 x 151/2 x 3/4 in
21-digit abacus of Korean form with 1 bead in heaven and 5 beads in earth. This type was used in Japan from the mid-1800s until the 1930 redesign that reduced the number of beads in earth from 5 to 4.
Pre-computer/abacus / soroban
Abacus; Suan pan; Mechanical calculation; Hand calculation; Asia
Gift of Gwen and C. Gordon Bell