New Zealand 1975 20c struck on Scalloped Planchet
In 1975, New Zealand's 20c pieces were struck by the Royal Mint, Llantrisant. Among the 5,027,000 20c pieces struck in Wales, a small number were struck on scalloped edged planchets.
In 1975 the Royal Mint, Llanstrisant was also striking coins for Hong Kong, including the first striking of the Hong Kong $2 coin, which was struck with a scalloped edge. No doubt a small number of Hong Kong $2 planchets were accidentally mixed in with New Zealand 20c planchets, leading to the striking of a small number of wrong planchet New Zealand 20c pieces. It is unknown how many were struck: one was sold in Mowbrays numismatic auction 31 in September 2023 as lot 359, but no doubt there are other examples.