The place where Iron Chef battles take place.
The backstory is that Takeshi Kaga is a disaffected rich gourmet with a penchant for wildly extravagent clothing. (He especially likes ruffles and sparkly capes.) Grown bored with his life, Kaga formed the Culinary Institute, becoming its chairman, and built the stadium. He began searching out the top men of various styles of cuisine, naming them the Iron Chefs. In the stadium they do battle with other top chefs from around the world, vying with each other to create the most original and exciting dishes using a secret theme ingredient, unveiled by the Chairman with a flourish at the beginning of each battle. "Allez cuisine!" he cries with a bad French accent, and the chefs scurry up to the dias in front of Kaga to grab their black pigs or peaches or unisex salmon or whatever the theme is, and then run back to their stations to begin cooking.
Kitchen Stadium as it appears to us, the viewing audience, is a small-ish arena with two complete kitchen areas, one for each chef. Above and behind the challenger's area is the "royal box" where his or her supporters sit. On the other side is a table for commentators Fukui Kenji, Hattori Yukio, and the ever-changing cast of supporting actors and sportscasters who will take part in the actual "tasting and judgement". Behind the kitchens loom giant pictures of Iron Chef French Hiroyuki Sakai, Iron Chef Japanese Masaharu Morimoto, and Iron Chef Chinese Chen Kenichi. Poor Iron Chef Italian Masahiko Kobe, who joined the august group later, must be content to have his picture off to the right side. The chefs ascend into the stadium in front of these pictures when summoned by Kaga to do battle.
On the day of a battle the stadium is humming with activity, as the chefs and their assistants rush about the kitchen preparing their masterpieces, closely watched by film crews and a team of note-takers, who relay their information to floor reporter Ota Shinichiro. Ota gets the attention of the commentators by calling "Fukui-san!", then breathlessly describes what's in every mixture in loving, but very speedy, detail.
Though I read somewhere that the stadium is supposed to be in Kaga's castle, it is in fact a TV studio. The unofficial website for the show, www.ironchef.com, has photos of the stadium, which when the show was in production was apparently dismantled and reconstructed every week, and tells how to get a tour of the site.