Tekka don, a.k.a.
Tekka-Don, is a dish that can occasionally be found in a
Japanese Restaurant. As stated in
other writeups,
don means something along the lines of "over
rice."
Tekka means "Iron Fire" or hot iron. When an iron gets really hot it turns red, the same color as
tuna. Thus
Tekka Don is "Fillets of
Tuna on a bed of
Sushi Rice."
abandon all hope adds that Tekka can also mean tuna, and the name is a play on words because of Tekka's dual meaning and the similarity of color.
Personally I love this dish. I don't know what is the "correct" way to eat it, but I like to mix my soy sauce and wasabi in the little dipping bowl and then pour it over the bowl. Then mix up another batch and that to dip the fillets in.
Similar dishes: Katsu Don (Cooked Pork Cutlet and Egg), Oyako Don (Cooked Chicken & Egg), Unagi Don (Eel), Ten Don (Tempura), Chirashi Don (various), and others.