I have a simple question about the PC Engine Hu-Card games. Many of the games have a Volume listing in the top right corner. For example, Ninja Gaiden is Vol.47, Image Fight is Vol.3, Populous us Vol.37, ect.. Now, at first I thought this was the actual number of the game, as they were released. However, looking at the dates of the games, that doesnt seem to make sense. Take Image Fight for example. Its Vol.3, but dated 1990. Now, knowing the PC Engine was released a few years earlier than that, the number doesnt make sense to me. It cant be the 3rd game released. So, Im curious. What exactly is the Vol. #? What does it represent?