BLOG - Yu-Gi-Oh - Series 1
Series 1 was the first series of Yu-Gi-Oh! cards to be released for the Yu-Gi-Oh! Official Card Game by Konami, and consisted of 14 Booster Pack sets (seven each in the Vol. and Booster series) released between January 23, 1999 and March 1, 2000.
BLOG - Yu-Gi-Oh - Series 2
Series 2 of the Yu-Gi-Oh! Official Card Game covers set releases of the period between April 1, 2000, and March 21, 2002. The series debuted a new card layout, and new sets consisted of 50 or 51 new cards. In addition, many Series 1 cards were reprinted in separately-named sets (Vol. reprints) or "Booster R" sets (Booster reprints).