Featuring whale meat in a barbeque-like sauce between two slabs of pressed rice instead of bread, the Whale Rice Burger retails for 300 yen ($2.30) compared with 85 yen for a McDonald's hamburger.

At lunch yesterday, a line stretched back from the take-away window where owner Yoshiaki Nakagawa was doing brisk business in whaleburgers, a fried whale cutlet sandwich and a whale hot dog.

"I really wanted to come up with something with whale in it that people could eat casually and cheaply, as a take-away item," Nakagawa said.

"We are the only place that provides this," he added proudly.

Whale was an important protein source for an impoverished Japan in the dark days just after World War Two, but has become an expensive, gourmet food that rarely appears on family dinner tables and can usually only be eaten in a handful of speciality restaurants.

While older Japanese remember eating whale fried or stewed in school lunches, the meat is an unusual food for younger Japanese who may be more at home in McDonald's than a traditional Japanese restaurant.

Nakagawa, who also runs a sit-down whale restaurant and a store selling items such as raw whale meat, salted whale skin, whale bacon and thinly sliced whale tongue, said this lack of interest in whale was one of the inspirations for his invention.

"We have a long history of eating whale in Japan, and I wanted something that would appeal to young people."

This week, his first day of business, he sold 30 whaleburgers, 100 whale cutlet sandwiches and 20 whale hotdogs.

Customers gave the whaleburger mixed reviews.

"It was really delicious," said Takeshi Matsumoto, a 30-year-old office worker who recalled eating whale in primary school. "It tastes just like any other hamburger."

His wife Nami said the meat was tough.

Mayumi Hamasaki, who had the whale cutlet sandwich, said she had expected a more unusual taste sensation and was unlikely to buy it again.

"I wanted more of a typical whale flavour and aroma."