Passage: The currency became legal tender in China commencing in 1937. It was later replaced by issues from puppet banks. However, the currency remained in force in Hong Kong between 1941 and 1945. Initially set at HK$2 = JMY1, the Hong Kong dollar was largely preferred by locals and hoarded away. In order to address this, the Japanese government made possession of Hong Kong dollars illegal in 1943 and required a conversion to JMY at 4 to 1.

Question: When did the Hong kong dollar become legal tender?
1937