Counting rods (decimal place-value numerals)
Varillas de cálculo con numeración decimal posicional
- Date
- c. 400 BCE · confidence medium
- Place
- Central Plain, Henan, China
- Credited to
- Calculators of the Warring States period
- Field
- Knowledge & symbols
⚠️ Disputed: the sources disagree.
What it is
Bamboo or bone sticks placed on a surface in columns of units, tens and hundreds, alternating orientation and leaving gaps for zero. It was the first fully operational decimal place-value system and the tool with which all classical Chinese mathematics was done.
Shang inscriptions already use a multiplicative decimal system, but positional notation with rods is only documented from the Warring States period. Its possible influence on Indian numerals is an unproven hypothesis.
What it led to
- efficient decimal arithmetic
- solving linear systems on a counting board
- positional notation for polynomials in Song-Yuan algebra