These cards were issued by American Sweets, Inc. out of the Philippines. According to this Net54 post, only 40 cards are known.
More, however, were supposed to be printed. The exact number seems to be up for debate, though. As stated on the cards themselves, 250 were to be printed. Wrappers, however, say only 140 cards. Whatever the number, that does not appear to have happened as the Japanese invasion of 1938 is cited as the culprit for it not being completed.
The cards themselves are extremely rare. Today, most of the cards have only one known copy.
Cards feature crude color cartoon pictures of boxers that are similar to what you would find on a strip card. The boxer’s name is printed in different parts of the background area, varying by card, along with a card number.
Backs of the cards include the American Sweets name as well as a biography of the subject. In addition to boxers, the set includes wrestlers and weightlifters. But because the entire series was not likely finished, how many of those subjects that were printed is unclear.
The categorization of the set is worth noting. The cards have an N-Card designation from Jefferson Burdick in the American Card Catalog. While N-Cards are recognized as 19th Century issues today, at the time of Burdick’s book, it simply was used for Central American cards. Specifically, these cards have an NX designation – the ‘X’ denoted that the cards were in the miscellaneous category.
1938 American Sweets Knockout Bubble Gum Set Checklist
This checklist is obviously far from complete. I have documented the known cards I have seen to date.