"The Seibu Lions" is a yonkoma, which appeared at the end of the fourth chapter of the Yu-Gi-Oh! GX manga.
- Just outside the Tokorozawa Dome, Naoyuki Kageyama narrates that he's a huge Lions fan and goes to the Tokorozawa Dome when he has time, as he lives nearby.
- There aren't any seats in the outfield, so he sits on artificial turf.
- A common sight before the game is children playing the Yu-Gi-Oh! card game.
- But the moment the players come near, the children leave their cards behind and run over to ask the players for autographs.