Restaurants in Yokosuka, Kanagawa Prefecture, began offering a hamburger Friday based on a recipe from the U.S. Navy to help it attract tourists and promote friendship between the city and the military base.

The Yokosuka Navy Burger is available at four restaurants chosen by the city, which wants to promote it as a local specialty. Six other restaurants will begin putting it on their menus by mid-February.

The burger features a 200-gram ground beef patty but with less salt and sauce than other burgers so customers can fully savor the flavor of the beef, the restaurants say. Each restaurant also uses a secret ingredient.

Among the four restaurants is Tsunami, a Mexican restaurant just in front of the base, which also serves an extra-large burger called the George Washington, after the nuclear-powered aircraft carrier that was deployed to Yokosuka last September.

"I want people to come to Yokosuka to taste it," said Shigeru Iida, the 55-year-old owner of the restaurant.