Idols are no longer just the domain of cute girls who can't sing or pretty girls wearing bikinis.   Young women with pretty looks and a profound knowledge of history are establishing a niche for themselves in a new category of celebrity with the moniker of "rekishi aidoru" ("reki-doru" for short) or history idol.

A recent Tokyo event for fans of the historical novel Romance of the Three Kingdoms featured Mikako, 24, dressed as Zhuge Kongming. The venue, with a capacity of about 50 people, was packed.

"History is still a minor hobby, so I welcome these so-called idols helping to spread it," said a female participant in her 30s.

Mikako

Mikako became a model following a stint as an office worker after college. She was invited to a history event this summer for the first time and became to be known as a "history idol." These days, she not only appears at history events but also at college festivals.

"There are many people who are called idols, but you have to have an expertise to survive in this field," says Mikako.

Mikako's favorite time period is the final years of the Edo period. She even exchanged letters with the head of the Ryoma Sakamoto Memorial Museum, which celebrates the life of the prominent figure at the end of the shogunate.

"I'm still learning about Romance of the Three Kingdoms, and reading the books by Eiji Yoshikawa and the manga comic books by Mitsuteru Yokoyama," she notes.

Eri Kohinata

"One of her appeals is that she's not like those slow-witted girls popular on TV shows," explains a 24-year-old history-idol fan.

In addition to their looks, history idols must be recognized for their knowledge by history fans. "You cannot call yourself a history idol," declares the president of an online apparel shopping firm who is said to have coined the term. History idols must possess a level of knowledge that satisfies even history nerds.

Another popular history idol is Eri Kohinata, a 20-year-old student at the Yokohama National University.

Women make up roughly half of Kohinata's fans.

"History fans are a devoted group of people, and I was not sure at the beginning if it was okay for me to be called a history idol," Kohinata says. "But I'm relieved that they are surprisingly happy with me."

Kohinata is now studying the Warring States Period of Japan, and her interest in Yukimura Sanada even took her to a pilgrimage to his graveyard.

History fans enjoy themselves talking with their reki-doru in a recent event in Tokyo.

The creation of history idols is attributed to the increase in female history fans. Amid the boom of video games and manga about Romance of the Three Kingdoms and Japan's Warring States Period, many started reading original novels, soon becoming history experts.

These video games captured the hearts of women with the appearances of the characters; even though warlords may be stern-faced in pictures of history textbooks, they have modern-looking, handsome appearances in the games.

"Women now account for 30-40% of buyers," says history-themed video game producer Koei Co.