O.M.G. Burgers (a hamburger restaurant in Kanagawa) touts a monster sandwich they call the Akebono Sumo Burger on their webpage. It weighs approximately 6 pounds and comes with about 2 and a half pounds of fries. If you manage to finish it, you win the equivalent of 300 USD and a t-shirt that proclaims to the world you ate half a cow.
Oh, and the burger is on the house.
For the ex-pat-- and the native-born as well-- Japan offers a wide variety of hamburger dining experiences. You can try the classic taste of McDonald's (yes, yes I did), Burger King and Wendy's (they exited the Japanese market in 2009, but this December they're jumping back into the food fight with renewed vigor), plus the home-grown delights of Freshness Burger and Mos Burger. If you're a fan of the manga Nana (and why aren't you?), you can try a Jackson Burger at Hachi's favorite place, Jackson Hole. Which is a bar.
But not the original bar as seen in the comic book and movie. In 2008, Jackson Hole moved from near the southern entrance of Chofu Station to new digs on the northern side, as some intrepid explorers in real-world manga locations have discovered. Philosophers and those versed in mereological essentialism will have to debate whether or not a Jackson Burger in the new location is the same as a Jackson Burger at the old and if it presents a Ship of Theseus paradox. I just know Hachi loves a Jackson Burger no matter where she sits to eat it.
As for me, a trip to O.M.G. Burgers is on my itinerary for the coming year. After all, who wouldn't want to challenge the sumo burger, especially if there's a chance some bikers will be there to cheer you on?