Kanto vs. Kansai Regions
Here's some traditional and anecdotal differences between Kansai and Kanto.
Of course, just because something is "Kansai" style, it doesn't mean that it can't be found in Kanto and vice versa.
* Udon vs Soba
Wheat is from Osaka plains, Buckwheat is from Nagano.
* Light vs Heavy flavouring
Usukuchi (light soy), Saikyo miso ("Western capital" white miso) and snowy tempura is preferred in Kansai. Koikuchi (dark soy), Akamiso (red miso) and golden tempura is preferred in Kanto.
I think it's because usukuchi & salt allows the konbu to shine (konbu used to be distributed via Osaka), but koikuchi can stand up to the strong flavour of bonito (aka, katsuo, which was highly prized in Tokyo).
* Fugu vs Ankou
Pufferfish/Blowfish is preferred in Kansai, Anglerfish/Monkfish is preferred in Kanto.
* Oshi-zushi vs Nigiri-zushi
Pressed sushi is sometimes called Osaka sushi, whereas finger sushi is referred to as Edomae (Tokyo-style) sushi. Kansai and kanto also differ when it comes to chirashi-zushi - Kansai style has no raw fish, wasabi or additional soy sauce. It is instead seasoned with dashi.
* "Sukiyaki" vs Sukiyaki (originally "Gyu-nabe")
In Kansai, they're supposed to grill the meat, before simmering the other ingredients, and use soy sauce and sugar. In Kanto, the meat is simmered with the other ingredients in warishita broth.
* Unagi: Hara-biraki (Belly-opened) or Se-biraki (Back-opened)?
In Kansai, unagi is cut across the belly and grilled ("talking with your stomach open" apparently means speaking frankly) before serving whole. In Kanto, the head and tail is removed before slicing along the back (slicing the belly would be inauspcious for samurai, who were more prevalent in old Tokyo than Osaka). After this, it is steamed before it is grilled (the kabayaki style is from Tokyo).
* "Niku": Beef or Pork?
Kansai seems to have been cattle country, so beef is more commonly eaten than pork. Conversely, in Kanto, meat dishes like "nikujaga" and "katsu" are more likely to include pork than beef by default. On a related note, "natto" is less likely to be eaten in Kansai as it was considered cattle feed.
There are further regional distinctions as well; one notable example is the city of Nagoya, which is situated halfway between Osaka and Tokyo.
* Udon vs Soba?
One of the famous products of Nagoya is "kishimen," which is made with wheat flour, like udon. However, the noodles are flat noodles (thin and wide). There is also a local ramen variation, the spicy "Taiwan-ramen."
* Light vs Heavy flavouring?
Nagoya is also famous for Hacho-miso; which is like red miso, but saltier and heavier. It is used in a lot of local dishes, such as miso-nikomi-udon and miso-katsu (and miso lager, miso sours and miso creme pudding!).
* Unagi: Hara-biraki or Se-biraki?
Nagoya is well known for eel, and the local preparation is called "hitsumabushi," which involves cutting the eel into small pieces and serving it over rice.
* "Niku": Beef or Pork?
In Nagoya, nikujaga can be made with chicken, rather than beef or pork. Nagoya is famous for its local "kochin" chicken, which is also used in tebasaki: marinated chicken wings.
In Kansai, you will have the omusubi, butaman, the sweetened sushi like hakosushi... in Tokyo the onigiri, the nikuman, the Edo-mae sushi.. So that means that consommation of sushi is different as Tokyo eat 10 times more maguro that Kansai and the contrary on white fish...Besides sushi, Tanuki soba will be radically different, the yakisoba also...