Handheld Soviet USSR Wooden Abacus Black Brown Beads

Small handheld wooden abacus is built on a wooden frame with metal rods holding reddish brown and black beads. The abacus was meant to be handheld like a book, so the vertical sides of the frame are slightly curved to allow it to be easily held in the user’s hands. Excellent original condition. Beads slide easily without hesitation. Maker stamp on inside written in Russian. This is a Russian abacus as it has ten beads on each wire, except one, that has four beads. The row with four beads was used to calculate quarter-ruble fractions. The abacus has a total of eight rows. The number of rows places this abacus after 1916, as a Russian abacus prior to this time had an additional four-bead row. Dimensions 4.24 inches X 6 inches X .75 inches