# The Schoty

A Schoty and a Modern PDA: A Handspring Visor, displaying a calculator, next to a schoty.

The Russian abacus is called a schoty (pronounced SHAW-tee). It was invented in the 17th century and is still in use today. The abacus is operated by sliding the beads right-to-left.

## Design

The design of the schoty is based on a pair of human hands.

If you hold out both hands in front of you, palms facing out, you will see that your 2 thumbs are beside each other and 2 sets of 4 fingers spread out from there. Similarily, on the schoty, each row has 2 sets of 4 beads of the same colour on the outside, representing the 2 sets of 4 fingers and the 2 innermost beads of the same colour representing the 2 thumbs.

The "home" position for the beads is on the right hand side. The bottom-most row represents 1s, the next row up represents 10s, then 100s, and so on. So, counting is similar to counting on one's fingers, the beads move from right to left: 1 to 10, and then carrying upwards to the next row.

Annotated schoty: The numbers on the right are multipliers for the beads in the corresponding row. (Click for a larger view).

Lev Kirischian, a researcher here in the Electrical and Computer Engineering Department (whose schoty is shown), notes that schotys with 20 beads on each row, are of Georgian (once a Soviet Republic in the southern USSR, now an independant country) origin-- Georgians counted with both their hands and feet because the relatively warm climate allowed them to wear sandals and thus the exposed toes were also used for counting.

Careful observers will note that the metal rods, on which the beads slide, have a slight curvature to prevent the "counted" beads from accidently sliding back to the home-position.

Also see Sergei Frolov's site about Russian Calculators.