There’s an older thread about the Chinese Championship Arena card here: www.elitefourum.com/t/chinese-championship-arena/10882/1. It reveals that the card was a participation reward for attending training sessions at various locations around Taipei for 17 days in September 2006 ready for the opening of PokéPark.
It speculates that the card had less than 100 copies distributed (less than 6 cards per day), but considering Taipei is a pretty largely-populated place I can only assume this would be much higher.