Pull up to a roadside restaurant in the mountains of Hiroshima and you may be bewildered to find something called ‘wani’ on the menu. Since ‘wani’ means ‘crocodile’ in Japanese, and these large, aquatic reptiles aren’t common in Japan, you could be forgiven some confusion.

But the mystery is easily solved. Wani is an archaic word for shark, and it’s still commonly used in the San’in and Chugoku regions to the north of Setouchi. The normal Japanese word for shark is ‘samé’, a type of fish not commonly eaten in most regions of the country. But there’s a reason why ‘crocodile’ is quite the delicacy in Japan’s mountainous inland areas.

Because shark meat contains high levels of urea, it doesn’t spoil easily. It also contains significant amounts of trimethylamine-N-oxide, which suppresses the formation of histamine that causes food poisoning, and also prevents lipid deterioration due to oxidation. Consequently, in the days before refrigeration, sharks were the only fish that could be eaten as sashimi in inland areas far from seaports. Since all true Japanese long to eat raw fish, shark meat was a highly desirable commodity in mountainous areas where fresh seafood was otherwise hard to come by.

The shark eaten in this area is caught in the Japan Sea off Shimane. About  twenty species of sharks are eaten, including salmon sharks, mako sharks, hammerhead sharks, sandbar sharks, and thresher sharks. Depending on the species, the colour of the flesh varies from light pink to red. When even shark was a rarity in places like Shōbara and Miyoshi, it was traditionally eaten at New Year and other festivals as a treat. Fifty percent of all shark shipped is still eaten at the turn of the year.

So what does ‘crocodile’ taste like? Is it good to eat?

Yes, it is. When it’s fresh, it has a very soft texture and mild, slightly sweet flavour. This is due to its low fat content and the natural sweetness of trimethylamine-N-oxide. Although it’s traditionally served with chopped ginger and spring onions, the best way to enjoy shark sashimi is on hot rice with just a dash of light soy sauce. Nothing else is required.

Perhaps the chopped ginger is a holdover from the days when the shark had more of a bite. Trimethylamine-N-oxide and urea decay into stinky trimethylamine and ammonia, also raising the pH of the meat. By the time it reached its consumers in the days before refrigerated trucks, it had often begun to pong. Some people liked it like that. It was sometimes remarked that “Wani is so tasty, even the neighbours can enjoy it”.

These days, shark is often served deep fried as cutlets or burgers, but this method of cooking renders it flavourless. So we recommend enjoying it in the manner for which it was originally prized, as sashimi with rice.