The 'sushi terror' pranks thrusting Japan's restaurants into chaos
By James Gray, Multimedia Producer
Japanese police have arrested three people on suspicion of taking part in so-called "sushi terror" pranks.
In recent months, the acts have become more commonplace, with videos populating social media platforms under the trends #sushiterror and #sushiterrorism.
Sushi restaurants have called out the pranks as "extremely malicious" and threatened legal action against any perpetrators who are caught.
But exactly how do the pranks work and what has been the reaction to them?
What do the pranks involve?
Videos have been made of people spoiling other diners' orders at sushi restaurants which use conveyor belts - known locally as kaitenzushi or in the West as 'sushi trains' - to pass food. It is not understood what is motivating people to commit the acts.
For example, the pranks have seen individuals lick shared soy sauce bottles or touch sushi plates, which do not belong to them.
They aim is to carry out the acts without those they are pranking becoming aware of what has happened.
Is the trend new?
No. Restaurants in Japan have been dealing with such incidents for a number of years, though the frequency of pranks have been growing.
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What have the recent arrests centered on?
A 21-year-old and two teenagers were arrested for allegedly taking part in a prank at a Kura Sushi franchise, in the city of Nagoya, according to Japanese broadcaster NHK.
The oldest culprit is alleged to have put his mouth on the spout of a soy sauce dispenser.
How have the pranks been received?
Sushi restaurants have spoke of their concern at the trend, which has seen some, including Choushimaru, cease the use of conveyor belts in its buildings.
Others are asking customers to approach members of staff for condiments and utensils, while table service only rules are now also being applied.
Kura Sushi has said it hopes the recent arrests will reinforce to diners that "actions which undermine our trust-based structure for our customers is a 'crime'".
A spokesperson said: "Our company will continue to strive to further improve the system to prevent such nuisances so that customers can enjoy their meals safely and comfortably.
"We will continue to do our best to grow the conveyor belt sushi culture that is dear to Japan globally."
The firm has said it will use artificial intelligence (AI) operated cameras to monitor customers to see if they are misbehaving.
Members of the public have also voiced their displeasure at the pranks. In February, a video of a man licking a bottle of soy sauce before placing it back onto a conveyor belt sparked outcry.