2005 was the Year of the Rooster according to the Chinese lunar calendar, and this year marked the beginning of the third iteration of the ever popular Lunar series – second only in popularity to the widely recognised Pandas. The first Lunar series began in 1981; the second in 1993. Colourised Lunar coins had made their first appearance in the series back in 1998 as part of the Year of the Tiger set of issues, but this was not the first time colour had been used to enhance and add a new and different appeal to modern Chinese coins.
At this early stage, the China Mint was commissioning its colourised coins from Swiss mints, presumably because the technology required was already at a developed stage in Switzerland, whereas in China it was in its relative infancy. Today most of the colourised coins available are now struck in Chinese mints, although this change only occurred as late as 2009, with the China Mint relying on the Swiss mints for their...https://www.chinesecoins.com/coin-orientation-the-2005-year-of-the-rooster-110-oz-colourised-proof-gold-coin/