Photo/Illutration Tomokazu Inui examines a patient in a Simba costume from "The Lion King" in Hitachinaka, Ibaraki Prefecture. (Kaede Sano)

HITACHINAKA, Ibaraki Prefecture--Around Christmastime in 2015, physician Tomokazu Inui decided to get in the festive spirit and treat his patients dressed as Santa Claus.

That was when he had an epiphany.

More than four years later, the ear, nose and throat doctor at the "Thank You Jibika Clinic" treats his patients posing as Mario, Aladdin and myriad other characters.

His patients have never been happier.

Inui, 40, who opened the clinic in his hometown here in November 2014, shed his white coat for cosplay outfits to cheer up patients despondent about illness and turn around the sterile image of doctors and hospitals in general.

"I wanted patients to feel closer to me and transform the clinic into a place of smiles," he recalled.

After receiving an overwhelmingly positive response to his St. Nick get-up in 2015, Inui thought, "I should keep doing this."

The following February, he donned a red ogre costume on Setsubun, the day before the start of spring.

In May, he dressed as Kintaro, the mythical hero of Japanese folklore celebrated on Children's Day.

"It's fun," a patient said.

"I like it, because it's cheerful," another said.

Encouraged by the feedback, Inui started purchasing more costumes over the Internet. He even handmade one of Simba, the main character in "The Lion King" franchise.

It has gradually become a near-daily affair for Inui to see patients dressed in a costume.

In all, he possesses about 30 outfits, including Mario from the popular Super Mario Bros. video game series and Aladdin from Disney's hit animation of the same name. He sometimes even impersonates a clerk at a convenience store.

With "fun" and "appreciation" the clinic's motto, Inui rotates his costumes every two weeks or so.

Donning the playful attire, he always says "Congratulations" to a patient who has completed treatment or recovered, sending them off with a smile and applause.

Eliciting a smile from patients is an everyday pleasure of being a doctor, he said.