The notice board of a local pub advised of the pub’s activities on ANZCA DAY, presumably commemorating the college of anaesthetists, or chartered accountants, or Australia, New Zealand and California, or Canada, or any one of the 315 other people, places and things listed on The Free Dictionary’s acronym finder. Several days later, that had been changed to ANZAC DAY, commemorating the Australian and New Zealand Army Corps.
See here for a discussion about whether it should be ANZAC or Anzac (and also generally on acronyms and initialisms. The public holiday is officially Anzac Day. (The pub’s notice board has upper-case plastic letters.)
Also note the Australian, New Zealand and Canadian involvement in the Battle of Gapyeong (22-25 April 1951).
Never Pure and Rarely Simple 