This is an AUTHENTIC BRITISH ROYAL NAVY H. AMETHYST YANGTSE 1949 RARE CHALLENGE COIN. On 20 April 1949, during the. Bernard Skinner, was cruising on the river Yangtze from. Which had been posted as. For the British Embassy there. According to the Royal Navy, at about 08:31, after a burst of. People’s Liberation Army. On the north bank of the river fired a salvo of ten shells to warn Amethyst to stay away from the war zone. Therefore, Amethyst ignored the warning and continued to cruise towards Nanking. Speed increased, and large. This coin is from a private collection and is 100% authentic.