Tokyo  - Japan's hottest new idols are busy not only brushing up their appearances, but also their inner beauty by cramming on East Asian history to maintain the title of reki-doru or history-buff idols.

The erudite idol genre grew from the popularity of a Japanese video game focusing on the nation's 15th and 16th centuries war-time era and popular manga comics depicting China's Romance of Three Kingdoms. This has helped boost clientele, according to Japan's business daily, The Nikkei.

"There are many people who are called idols, but you have to have an expertise to survive in this field," The Nikkei quoted reki-doru Mikako, 24, as saying.

The office-worker-turned model awaits results of a qualification exam on the 19th-century ronin, Ryoma Sakamoto, her hero.

Mikako likes visiting the graves of historical figures and her special talent lies in reciting the dying words of samurai warriors in late 1800s of Edo era, she writes on her website. This may be another reason why she is respected by her many fans.

Japanese culture creates pop-culture icons who are looked up by almost every generation. They include Japan's original idols such as the reki-doru, gura-doru (short for gravure idol in Japanese), may-doru (maid idol), chika-doru (underground idol) and baka-doru (idiot idol).

The concept has been spreading since the 1980s, when female singers appealed to their fans with their innocent beauty - and little talent in vocal performance.

The term began to attach itself to other icons in the diverse industry, not limiting itself to mainstream pop culture, but usually describing a beautiful woman with expertise in a particular field.

Gravure idols, gura-doru in Japanese, became a career title for women who decorated weekly magazine covers, photo books and profile videos in sexy poses and often in bikinis.

May-doru dress up as maids at Tokyo's famous maid cafes, where otaku anime and tech nerds come to sip coffee and tea served by waitresses in maid costumes.

In their own circle, the title goes to compassionate idols who serve the needs of their customers and look best in maid costumes.

But make no mistake: as long as they possess the gifted looks, some idols can get by without any expertise or they can even turn their lack of talent into an attribute.

In contrast to the brainy reki-doru, the baka-doru seized their fans' hearts with their ignorance or feigned ignorance. Their marketability is simply in being regarded as idiots.

Baka-doru Mai Satoda said she has no recollection of anyone actually telling her she was an idiot.

"I wonder if people call those who answer questions honestly 'idiots'," the 24-year-old singer told Japanese media.

But another baka-doru, 22-year-old singer Suzanne, said it's all just part of her act.

"The ignorant facade that I put on is only a way to become a big star," Suzanne told a Japanese paper Naigai Times. "If I cling to the character too long, people will give up on me and I'll disappear from the showbiz in no time." (dpa)