Police will be on full alert in Tokyo ahead of the festive transition from the Heisei to Reiwa era, with several thousand officers to be dispatched on security duty over the coming days.

The Metropolitan Police Department plans to take maximum security measures in the areas around the Imperial Palace to guard against possible terrorism and disruptive activities by extremists. Riot police will also be sent to Shibuya, a popular gathering spot for young people during big events.

The Emperor’s abdication ceremony is set to take place Tuesday and will be followed by the crown prince’s accession ceremony on Wednesday. Both ceremonies will be held at the Imperial Palace.

Police vehicles will encircle the palace to protect it from possible acts of terrorism in which cars are used as weapons.

Radio transmitters will also be deployed to intercept drone movements and prevent a drone-based aerial attack.

On Saturday, the new emperor will greet the general public from the palace. The MPD will implement security and crowd control measures on the assumption that about 150,000 people will turn out — roughly the same number who visited for the Emperor’s New Year Greeting in January.

A line of people hoping to enter the palace is expected to stretch about 500 meters from Tokyo Station in Chiyoda Ward to the Imperial Palace Plaza.

On Saturday, a one-kilometer section of Uchibori-dori avenue that runs along the palace between Ote-mon Gate and Iwaidabashi intersection will be closed for 11 hours.

Parts of some streets, including Uchibori-dori, Sotobori-dori and Aoyama-dori avenues will also be closed 10 times for up to 15 minutes across Tuesday, Wednesday and Saturday, when Crown Prince Naruhito travels between the Imperial Palace and Akasaka Estate in Minato Ward.

Riot police in Shibuya

In 1990 when the “Sokui no Rei” Ceremonies of the Accession to the Throne were held for the current Emperor, extremists opposed to the Imperial system were responsible for 143 guerrilla incidents across the country. Attacks included firing a mortar bomb at a facility related to the Imperial family and throwing firecrackers during a parade.

The MPD will be on full alert against possible bombings by international terrorist organizations and disruptive activities by extremists on Tuesday and Wednesday, when the Imperial succession ceremonies will take place, as well as Saturday, when visits by the general public are planned.

When the new era starts Wednesday, riot police will be dispatched to Tokyo’s Shibuya district, where about 310,000 people gathered the night of Halloween in October, causing a number of disturbances.

Crowds of young people and foreigners also gathered in Shibuya for the New Year’s Eve countdown event last year, some of whom were seen pushing and shoving riot police officers.

Nightclubs and other establishments in the district have also organized events Tuesday night where young people can celebrate as the clock passes into the new era. Some on social media are already preparing to celebrate the start of the new era, suggesting people shout “Happy Reiwa.”

The MPD is considering deploying a “DJ police officer,” who directs crowds in a witty and friendly manner.