Yakiniku literally means grilled meat. The best Yakiniku is found in Seoul, but if you're stuck this side of the Korea Strait, you can still get your red meat fix from an "viking" yakiniku restaurant like this one in Akihabara. Raw meat and vegetables are laid out smörgåsbord style and you take what you want back to your table to cook on the gas barbeque provided (maybe charcoal if you're lucky enough to find a genuine Korean style barbeque restaurant). Eat your fill of ロース (sirloin), カルビ (beef ribs), タン (ox tounge) レバー (liver) and other bovine organs wrapped in lettuce, with pumpkin, capsicum, side salads, rice, and something approximating kimchi within two hours for around ￥1000 each at lunchtime, and wash it down with a ￥800 not-quite-a-pint of beer while pondering where the restaurant makes its money. In the evenings and weekends, when the customers don't have to get back to work and can spend the full two hours stuffing themselves, expect to pay a lot more.
"All you can eat" is not the only option for yakiniku. Japanese beef restaurants range up to the ridiculously expensive, often serving Kobe or Matsusaka beef. Teppanyaki is a popular choice of Japanese cuisine outside of Japan largely due to the theatrics of the chefs, though they are hard to find within Japan, and when you do find one, you'll probably be cooking for yourself on an electric frypan (as opposed to a gas or charcoal grill of Korean style yakiniku) with no show off chefs in sight.