Yugioh God Cards - How to tell if yours is fake or real

Revised to include the GOD Cards from the Legendary Collection.As a collector of Yugioh cards, I have overpaid and been disappointed when I won an auction that includes the Yugioh God Cards and the seller claims all their cards are 100% authentic. I am writing this guide to help fellow collectors and players who don't know how to tell a fake one from the real one.
Back of the God Cards: The color on theback of the cardsshould match the color on the front. Slifer should have a red tinted back. Obelisk will have blue. Ra will have yellow. There WILL BE NO "Konami" on the top left of the card or the "Yu-Gi-Oh!"/Trading Card Games on the bottom right corner.
Front of the God Cards: Like all authentic Yu-Gi-Oh! cards, there should be a square foil on the bottom right of the card. If you tilt it against the light, it will show you the millennium eye and part of the words yu-gi-oh!. Next to the square foil will be the copyright symbol and "1996 KAZUKI TAKAHASHI". Check the spelling, some god cards has spelling mistakes in the copyright line.
On the bottom left corner, there should a japanese characters for the card series G4 and GBI series (see next section). If you have one of the other promos (YMA, DOD, JUMP), the card on the bottom left corner will say "This card cannot be used in a Duel." The new god cards from JUMP (37