In 2010 British TV series “Sherlock” episode 2 “The Blind Banker”, the smugglers used a set of mysterious symbols to pass on messages. Those symbols are in fact numbers written in “Suzhou Numerals”, which is an ancient way of writing numbers in China.
Suzhou numerals derived from a kind of rod numerals in ancient China, but different from the counting rods that were for math and engineering purposes, Suzhou numerals were mainly used for accounting and business purposes. It is much easier than the formal Chinese written numbers system, made it much easier for almost everyone to understand, no matter what their education levels were.
Today, in some of the small traditional stores in Taiwan and Hong Kong, Suzhou numerals can still be seen occasionally. But it’s gradually disappearing with the wide spread of western style supermarkets, where of course Arabic numerals are used.
In order to save the traditional culture, I developed a small online tool to convert numbers written in Suzhou numerals and Arabic numerals. In the following screen shot, it converted Pi into Suzhou numerals.