Many thanks to guest blogger Lily Liu for contributing the below post! Lily is a graduate student at the UBC School of Information and recently completed a Professional Experience with Rare Books and Special Collections Library.

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What’s That Number? A Thirty-Minute Dive into Deciphering a Traditional Chinese Numeral System

During my time working with the Lock Tin Lee fonds at the RBSC, I came upon a certificate that used a number I had never seen.

From my RBSC peers, I learned that this number belonged to a system called Suzhou numerals (苏州码子; 蘇州碼子). As per their namesake, these numerals originated from the Suzhou region in China and were a traditional numeral system used by the Chinese before the introduction of Indo-Arabic numerals. Due to its ease of use, the Suzhou numeral system was popular amongst merchants, bookkeepers, and other calculation-centric occupations. It is the only surviving variant of the rod numeral system still in use today and can be found in the markets, old-style tea restaurants, and traditional Chinese medicine shops in Hong Kong and Macau.*

But what was the number on the certificate specifically? It did not correspond immediately to any numbers on the comparison chart for Suzhou numerals.

Deciphering the number became a collaborative effort between my curious roommate, myself, and the comparison chart. Our thought process proceeded as follows:

Option 1: 42?

〤 and 〢 are accounted for, but there are two additional horizontal strokes to the right that do not correspond to any number immediately on the chart, and the strokes look too intentional to be a mistake.

Option 2: 417?

Perhaps the writer just really elongated the short vertical stroke on top of the Suzhou numeral “7” (〧), and just really missed the stroke’s centre positioning and shifted it to the left? Yes…we were pushing it.

Option 3: 422!

My roommate spotted the smaller text that noted exceptions to the standard comparison chart.

Essentially, because numbers 1, 2, and 3 all use vertical strokes in the Suzhou numeral system, adjustments to these numbers’ standard forms are made whenever they appear consecutively to avoid confusion. In our case, when two “twos” appear consecutively, their form changes to “〢二”: the certificate’s number is 422.

Between reading up on the system and our back and forth quibbles we took a total of thirty minutes to arrive at the answer—but what a satisfying conclusion it was!

*Please note: The overview above is paraphrased from Wikipedia pages on Suzhou numerals, which are below. A link about counting rods (算筹; 算籌), the ancient form of mathematical calculation in East Asia, is also below.

https://en.wikipedia.org/wiki/Suzhou_numerals

https://zh.wikipedia.org/wiki/%E8%8B%8F%E5%B7%9E%E7%A0%81%E5%AD%90

https://en.wikipedia.org/wiki/Counting_rods