Such membership certificates had to be carried around by members of the Chinese secret societies in Singapore for identification. This certificate was issued by the Tsung Sin Kongsi. The certificate can be identified by a three-sided numerical puzzle inside the top of the inner octagon, containing symbols which represent numbers that add up to fifteen whether read horizontally, vertically or diagonally. A similar feature can also be found on the grand membership society of the Ghee Hin Kongsi. Secret societies in Singapore were set up in the 19th century with increased Chinese migration to the British colony to provide mutual aid and support for the migrants. These societies had originated from the Tiandihui, which in turn was a local version of the secret society in China that was a sworn fraternity of men with the common aim of overthrowing the Qing dynasty and restoring the Ming. Various splinter groups (hui or kongsi) subsequently emerged among the main dialect groups.
