Instead of being put out to pasture, a former champion racehorse named Three Kings got a new mission in life, thanks to a kindly police officer.

Senior officer Akiko Mizuta helped the equine make the difficult transition from the track to the streets.

After his retirement from racing, the 11-year-old male horse, now named Reiko, became a member of the Metropolitan Police Department's mounted police unit.

Reiko routinely watches over grade-schoolers on their way to school in a residential area in Fuchu in western Tokyo, with Mizuta, 33, on his back.

"Good morning," she calls out to children and blows a whistle to usher them to safety across the crosswalk when the light turns green. "Stay out of trouble!"

The horse was given the name of Reiko in the first March after Japan's era name changed from Heisei to Reiwa, meaning that he has gone through intense training to become a full-fledged member of the police force.

But he couldn't have made it this far without the help of Mizuta, who has always stood by his side.

DIFFICULT ADJUSTMENT PERIOD

The MPD's mounted police unit is based in one corner of the nearby Tokyo Racecourse. Mizuta started riding horses when she was 7. It's been six years since she was assigned to her dream job, and Reiko is the first horse she trained.

The officer met Reiko in the summer of 2018 when the horse was being taken care of by a riding club in Kanagawa Prefecture. He made his debut in horse racing in 2011 and retired in 2015 after winning five horse races operated by local governments.

After the equine was seen moving his ears and being at ease when he was caressed around the neck, he was singled out for police duty because of his friendliness.

But the former racehorse was terrible at walking slowly, stopping frequently, and not performing other movements required for police horses. It was even difficult for Reiko to just stand on concrete after being used to running on grass and dirt.

The animal was also leery of transitions of color on the road surface such as at crosswalks.

Mizuta had been training Reiko to help him become accustomed to working as a police horse in situations such as crime prevention parades and traffic safety events, using stuffed toys as large as a human child, umbrellas and drum sounds.

When Reiko showed signs of frustration, such as kicking at the ground and moving his mouth in an irritated manner, Mizuta talked to the horse as she caressed his neck.

FIRST STEPS TO BEING A POLICE HORSE

In December last year, Reiko attended the Ceremony of the Presentation of Credentials for the first time. It is a ceremony where newly appointed ambassadors present their credentials to the emperor, making a round trip between the Imperial Palace and Tokyo Station in a horse-drawn carriage.

It is considered the first step to a successful career as a police horse because each of the 13 horses is required to stay focused and remain in line while sounds from the immediate surroundings and road conditions change every second.

Mizuta felt with her feet that Reiko's heart was beating faster than usual and his legs were trembling as she rode at the back at the end of the line. She even knew when he was feeling hesitant to step over boundary lines created by the slight change in the color shading of the asphalt.

"It's OK. You don't need to be afraid," Mizuta told Reiko as she lightly applied pressure with her feet to give a gentle push.

It took about 20 minutes for the carriage to make the round trip, during which time the officer made sure she looked commanding. Mizuta said she suffered from severe muscle aches because she also felt stressed during the trip.

"(Reiko) had been antsy at first, but he has become completely dependable," Mizuta said. "Now that he was given the name, it's finally time to become independent. I feel a little sadness, but I want to help him grow further so that he will stay calm when another member of the unit gets to ride him after I am transferred to another position."

Their morning duties have been put on hold after schools were closed on the government's request to prevent the spread of the new coronavirus.

Mizuta and Reiko are currently waiting in the wings while the officer and her partner devote themselves to training for a call of service in the days to come.

MOUNTED POLICE UNIT MORE THAN A CENTURY OLD

The Metropolitan Police Department is one of the three police headquarters that have mounted police units. It is a unit affiliated with one of the traffic police forces with 23 members and 16 horses.

The unit is in charge of watching over children on their school routes, in addition to attending traffic safety and crime prevention events at least 300 times a year.

The MPD's mounted police unit was founded in September 1903. Following the end of World War II, there was one time after September 1950 when the unit was in charge of crackdowns on traffic violations.

"It has been said that unit members went after violators hard," a representative said.

With the changing times, horses were replaced by police cruisers and motorcycles.

New horses will be added to the unit after they are selected from calm and healthy ex-racehorses kept by horse riding clubs in the Kanto region, paying a little less than 1 million yen ($9,180) for each.

Notable horses include Hercules sired by Deep Impact, a famed racehorse that died in July last year, and Tosho Sirocco, whose career earnings topped 300 million yen.

The Kyoto prefectural police and the Imperial Guard Headquarters also have mounted police forces.