The secret behind the hi-tech future of sushi lies in an unremarkable building in the backstreets of Osaka.
Inside, empty plastic cups and plates adorned with scrunched-up wet paper – to replicate the weight and texture of scallops – make their way along a conveyer belt.
To one side, concealed behind a plastic screen, technicians monitor data on computer screens, the specifics of their work deemed off-limits to the Observer and a small group of journalists granted rare access to the development “studio” belonging to Sushiro, the leading force in Japan’s multimillion dollar sushi train industry.
This is where developers make incremental improvements to the restaurant chain’s ability to deliver plates of freshly-made sushi to diners’ tables with lightning speed, and stay one step ahead of the competition in a sector estimated to be worth 740bn yen (about £4bn).
“In the past, diners used to take what they fancied from a free-for-all conveyer belt, but these days most people want to order their favourite sushi,” said Masato Sugihara, deputy manager in the IT department at Sushiro’s parent company, Food and Life.
The studio replicates a typical Sushiro restaurant. “Here we can ensure that the delivery system works properly and send the right order to the right customer as quickly as possible,” he said. “We can make tweaks, such as improving diners’ interface with the online menu, that we can’t make in real time at our restaurants.
“It’s not exactly top secret, but our neighbours have no idea what we do here.”
The holy grail of revolving sushi (or kaitenzushi) is flawless, contactless low-budget dining – a trend accelerated by the pandemic and a labour shortage that will leave Japan with an estimated shortfall of 6.4 million workers by 2030.
Not far from Sushiro’s secret nerve centre, staff are preparing for the lunch service at the chain’s outlet in the Namba district, one of about 4,000 kaitenzushi restaurants across Japan.
Diners at the 236-seat restaurant use a touch panel to choose from 150 items, from sushi and fried chicken to coffee and cake. Their bill is calculated automatically, and payment is made via a machine at the exit, where customers who have ordered takeaways online retrieve their orders from a bank of lockers.
It is a far cry from the traditional sushi joint of the popular imagination, where stern-looking artisan chefs with years of training place plates of lovingly prepared seafood on wooden counters.
But Nobuo Yonekawa, an expert on kaitenzushi, says the industry is losing its appeal amid rising prices and competition from other types of budget cuisine. “The number of customers is in decline, and to get them back the industry needs to think about technology in a different way,” said Yonekawa, who has written a book on the subject.
While there is no shortage of high-end establishments, sushi consumption has undergone a revolution since the first kaitenzushi outlet opened in Osaka in 1958. Purists may protest, but automation has made it possible to take sushi out of the exclusive, and expensive, realm of Sukiyabashi Jiro et al and turn it into a fast food to rival burgers and fried chicken.
Mass consumption of sushi has only been made possible by evolving technology, coupled with a cultural shift from gastro exclusivity.
At Sushiro’s Namba Amza restaurant, every single plate is fitted with a tag that makes it possible to determine in real time which sushi is selling well. The tags are read by sensors below the conveyor belt, ensuring that the correct order is sent to each table. Plates that aren’t picked up, and those on a second “free-for-all” belt from which diners can help themselves, are automatically removed after they have travelled 350 metres.
“We use AI to analyse which dishes are popular at particular restaurants, and order fish accordingly,” said Yutaka Sakaguchi, director of the IT department at Food and Life. “In the early days of kaitenzushi, chefs didn’t have a clear idea of what people wanted. They had to act on instinct.
“It enables us to cut down on food waste, but it also allows managers to predict with some confidence what kind of sushi to prepare and how many staff might be needed on certain days. It also factors in the weather … for example, what dishes are more popular when it’s warm and sunny. Before we had this system, we had a lot of food waste.”
At the back of the kitchen, a robot churns out tiny blocks of rice at the rate of about 3,600 an hour. “It’s impossible for a chef to do it that quickly,” said Yurika Murai, from Sushiro’s public relations department. Each block is identical and served up, as tradition demands, at skin temperature.
“The machine is programmed to make the sushi look like it’s been formed with human hands,” Murai added. “They’re not just soulless blocks of rice.” Further down the production line, another device wraps pieces of rice in nori seaweed for the chefs to finish plating and placing on the conveyor belts.
The rule is that sushi should be in front of the customer no more than three minutes after the order has come in. Yellow and red lamps light up to warn chefs that an order still hasn’t gone out.
“Our main challenge is to grasp at peak lunch and dinner times what fish is being ordered most,” Sugihara said. “You can’t just flood the conveyer belt with lots of plates, so we count the number of customers and the average number of plates being ordered at certain points in the day, and this allows us to anticipate demand during busy and slow periods.”
But there are certain tasks that are still the preserve of humans, such as slicing the fish and placing it on rice. “Clearing the plates and cleaning the tables is also difficult for machines,” Sakaguchi said. “But the labour shortage is making it increasingly hard to find new staff, so we need more automation. Maybe the answer lies in more robots, but we haven’t got there yet.”
Sushiro’s president, Koichi Mizutome, dismissed suggestions that hi-tech sushi has robbed the dish, which has been around in its recognisable modern form for about 200 years, of its culture and artistry.
“Our world is about automation and achieving the exact same level of service in all of our restaurants, where people can eat sushi at an affordable price,” he said. “The other [world] is about the individual touch by chefs who have gone through years of training. I think those two sushi worlds can coexist.”
