Counting Rod Tens Digit One

It marks the one in the tens place.

A complete rod numeral uses it for the tens place; it is not the ordinary Chinese character for ten, 十, or a complete number on its own.

Counting-rod notation alternates the orientation of signs in neighboring columns to distinguish place values. Its unit-place counterpart, 𝍠, means one in the units column, so the two signs are related but not interchangeable.

Where did this notation come from?

It grew from a Chinese calculation practice.

Chinese counting rods were in common use by the fifth century BCE; archaeological examples date to the second century BCE. The Nine Chapters, an early Chinese mathematics text compiled around 100 BCE–100 CE, describes rod calculations on a counting board for multiplication, division, fractions, and roots.

The notation later appeared in written diagrams and transcriptions. Unicode's reference set follows Song-dynasty conventions; Han-era material used the opposite orientation for digits and tens. In Japan the method is known as sangi, or counting rods, and Korean mathematics also adopted Chinese-derived rod calculation. As the abacus replaced rods for routine calculation, a 2004 Unicode proposal described the encoded forms' likely users as scholars of pre-modern Chinese mathematics.