Sumiko Iwamuro knows a thing or two about juggling work.

She spends her days behind the counter at a family-run specialty "gyoza" dumpling restaurant and nights once or twice a month moonlighting under her stage name DJ Sumirock. It is an impressive feat for someone 82 years old, although she insists otherwise.

At 2 a.m. when other octogenarians are fast asleep, Iwamuro -- donning her trademark sunglasses and bright red lipstick -- is spinning beats to the delight of the crowd at a dance club in Kabukicho, the famous red-light area in Tokyo's Shinjuku district.

"As long as you are not causing other people trouble, I think you are entitled to do whatever you want to do," Iwamuro, whose stage name is a combination of her first name and the translation of "Iwa" from her family name, said in a recent interview. "Age never matters...I'm still doing what I want to do and I'm so blessed."

She has been cooking gyoza since she was 19 at the restaurant her father started over six decades ago. Iwamuro manages to make several different dishes all at once, handling huge pots and frying pans on a big stove while memorizing the orders.

She says the multitasking of cooking is a lot like spinning vinyl and just as enjoyable.

"While keeping an eye on the fire, I'm also thinking in what order I should serve food to customers." DJ-ing also requires quick arrangements and spontaneity, but what is most similar, is that the result counts most of all, she says.

"Bad music will not get people dancing, vice versa, customers will eat only if the food is good."

Iwamuro first started DJ-ing when she was in her late 70s after her husband passed away. A French friend, who is now the owner of the venue where she performs, introduced her to club music.

To do it right, Iwamuro spent a year in training at a local DJ school. As she puts it, she didn't want to become merely "a performing monkey." She has improved to the point where she is invited to events not only in Japan, but has also spun in France.

Younger brother Masashi Iwamuro, 72, who also works at the restaurant, said his sister "has always been a person who is constantly on the go."

"I would say she is very greedy and has to try everything, but that is also what keeps her energy so high," he said.

A slightly tainted black and white family photo hanging on the wall at the dumpling restaurant shows Iwamuro as a little girl shyly grinning at the camera. The photo was taken at the start of World War II. Looking at her now, it might be hard to imagine the hardships she has gone through.

Born in 1935 in Tokyo, Iwamuro's life was always surrounded by music as her father was a jazz drummer. But his career was cut short when Japan entered WWII and jazz came to be regarded as the "music of the enemy."

Still, Iwamuro's passion for music never faded and the little girl continued listening to jazz through a gramophone, using blankets to muffle the sounds of the music.

The family's house was eventually burned down as the war intensified, forcing them to temporarily evacuate. After the war ended, Iwamuro's father started the dumpling restaurant and never returned to his music career.

The restaurant's background music is jazz, which may seem incongruous to some customers, but makes sense to those aware of Iwamuro's family history.

Iwamuro says she often reminisces about time spent with family, recalling memories that have kept her strong and helped her through life.

Iwamuro usually takes the stage with the theme from iconic anime series Astro Boy, known in Japan as Tetsuwan Atomu, a selection which sets her apart from most of her fellow DJs, many of whom are more than 50 years younger.

Astro Boy, a heroic humanoid robot, made his debut in a comic magazine in 1951, when the scars of WWII were still fresh in Japan and the country remained under U.S. occupation. Iwamuro said she chose it as her theme song as the character's birthplace, according to the comic, is the Takadanobaba area of Tokyo where she lives and works.

But once the club heats up, DJ Sumirock puts on a performance worthy of her rival DJs with the hottest selection of techno music.

"It's surprising that she's 82 but what is more important is that she can make you dance!" a 27-year-old man from France said.

DJ em, 30, who also performed on the same stage, said she hopes to still be spinning at Iwamuro's age. "I have learned from DJ Sumirock that you can reset your life any time and that it's never too late to do anything," DJ em said.

Iwamuro, for her part, wants people to recognize her for her music, not her age. "I want to be known for my cool DJ-ing."

She hopes to perform in New York one day and is also thinking about returning to horse riding and taking up the cello. "I never think about age and I plan to do whatever I want to do as long as I can move."