TOKYO -- Babymetal follows a tried and true formula for pop groups in Japan: trio of girls in fluffy dresses doing highly choreographed dance routines and singing with syrupy voices.

What sets them apart is their adrenaline-pumping, heavy-metal sound.

They have opened for top U.S. acts, played at famous venues in the U.K. and pulled off a successful world tour. Their growing popularity worldwide shows their novel combination of sweetness and high volume is a winner. It is rare for Japanese pop acts to find global success singing in their mother tongue. Babymetal's promoter, Amuse, believes the unique combination of sweetness and loudness is the secret of Babymetal's success.

Forever, baby

Formed in 2010, the all-teen group comprising Su-metal, Yuimetal and Moametal quickly rose to stardom in Japan, becoming the youngest female act to play the famous Nippon Budokan arena in 2014.

Overseas, the girls opened for Red Hot Chili Peppers' December show in London in front of a crowd of some 20,000. Opening for a major Western artist was a feat for a Japanese act, especially because it took place outside of Japan. "The show served as proof that Babymetal is here to stay for European and American listeners," said Amuse Managing Director Nobuyuki Soma.

In April 2016, the group performed solo at the U.K.'s renowned Wembley Stadium, another feat that no other Japanese artist has achieved. They also completed a tour of 10 countries in 2015.

Earlier attempts by Japanese artists to break into the global market include the duet Pink Lady and pop diva Seiko Matsuda, but few if any had significant commercial success outside Japan. Some critics speculate that earlier efforts were thwarted by the language barrier. Others said the Japanese sound did not appeal to Western ears.

Soma believes Babymetal's success owes a lot to the strategy Amuse worked out for them with the global market in mind. It fuses a heavy metal sound with the over-the-top cuteness of the Japanese pop idol. "It's what makes them so original," he said.

Akie Iriyama, an associate professor at Waseda University's Graduate School of Business and Finance, said Babymetal's success offers a good example of how winning business ideas can be found by melding disparate elements into something new.

Perfume is another trio of girls backed by Amuse that has found success overseas by combining techno music with cutting-edge augmented-reality technology. In their shows, images projected on stage interact with the human performers in real time.

The technology is provided by Rhizomatiks, based in Tokyo's Shibuya Ward. The company also produced the projections for Japan's presentation at the closing ceremony of last summer's Rio Olympics.

Yet another successful Amuse act is the four-piece rock band One Ok Rock, which combines melodic songs with lead singer who is fluent in English -- something hard to come by in Japan. The band has many fans elsewhere in Asia and drew thousands when they played in Shanghai and Taipei.

Amuse has some 300 acts in its portfolio, including big names like Southern All Stars, a rock band, and singers Masaharu Fukuyama and Gen Hoshino.

The company forecasts its group operating income for the year ending March 2017 will fall 34.8% to 3.9 billion yen ($34.5 million) due to a spike in its results the previous year created by a flurry of big shows by popular acts. But its earnings have remained resilient.

Last November, Amuse began holding auditions for multilingual actors and musicians, hoping to raise its profile in the global market.