Oden is usually served by the piece (rather than by the bowl). Japanese hot mustard (karashi, からし) is provided as a topping.
60 Year Old BrothThe best known oden restaurant is Otafuku (大多福) in Asakusa, Tokyo. It's been opened since 1916.
Oden is simmered for long periods of time in a light Japanese dashi broth. At Otafuku restaurant they haven't changed their broth since the restaurant burned down as a result of the firebombing of Tokyo in WWII.
Water and ingredients are continuously added to the broth but the broth is never changed. Each evening, the broth is carefully put in a large bowl and the stewing vat is cleaned. When the vat is clean the broth goes back in. They've been doing this since 1945.
Aged broth gives oden an edge that warms you up. Most oden restaurants endeavor never to change their broth — a 10 year old broth isn't unusual. Otafuku's 60 year old broth is considered the current champion.
Convenience Store Oden (コンビニ おでん)Some Japanese convenience stores sell oden in winter. As at Otafuku restaurant — the broth often looks like it has been sitting there forever. Nevertheless, people love it.
Festival OdenOden is a Japanese festival food. It's particularly popular at winter and early spring festivals (e.g. hanami).
Varieties of OdenThere are dozens of varieties of oden. The most common include boiled eggs, chikuwa (fish dumplings), kabocha (Japanese squash), daikon (Japanese radish), kombu (kelp), carrot, shiitake, octopus and atsuage (deep fried tofu).
Shizuoka OdenAs with most Japanese foods, there are many regional varieties of oden. For example, Shizuoka oden is skewered and has a stronger beef and soy sauce based broth.
Shizuoka also has a tradition of never changing oden broth. Aged Shizuoka oden broth is a dark black color.
Shizuoka oden is served with Japanese hot mustard, dried ground fish and seaweed powder as toppings.
Home OdenOden is easily prepared at home. Japanese supermarkets sell oden supplies in winter.
Oden PartyOden is considered a drinking food. Oden restaurants have a lively atmosphere. Many izakaya serve oden in winter.