I was looking through the mook about old Stadiums that Ryan bought for me last year and I saw a picture of this plaque in its original setting:
This plaque had actually marked the spot in the right field stands at Korakuen Stadium where Oh's 756th home run (which put him past Henry Aaron) landed. Of course, if I had noticed that there was an English translation on the display card in the Hall Of Fame, I would have known that - jet lag is a terrible thing (although I have no excuse for not having noticed this since I got home).
In honor of me finally paying some attention to what's in front of me, I thought I'd show a card with a picture of Oh reaching home after home run #756:
This is from the 2007 BBM Home Run Chronicle set, a box set containing the top 45 home run hitters (at the time of course) in NPB history. Oh's card is, of course, #01.