Chikuwa is a traditional Japanese fish cake using fish surimi with a hole in the middle. Fish surimi is wrapped around a thick metal or bamboo skewer and broiled or steamed. Broiled one is called Yaki-chikuwa but broiled chikuwa is most popular one sold in supermarkets.
Chikuwa is a common item for oden or nimono; both are Japanese simmered dish. Chikuwa-ten, chikuwa tempura is also a popular food mostly eaten together with udon noodle.
If you visit a izakaya tavern during your stay in Japan and if the izakaya has chikuwa no isobe-age, do not miss the chance to try it. Chikuwa no isobe-age looks similar to chikuwa-ten but the ingredients include nori seaweed. Then, chikuwa-ten is eaten with soy sauce or Worcestershire sauce, but chikuwa no isobe-age is eaten with mayonnaise.