In the fashion world, it's not what's in your head, but what's on your head that counts. A baseball cap? A beret? Or something a little more provincial, like a wool cap? Milliners spend a lifetime mulling such matters and creating new styles of headwear.

One up-and-coming star currently turning heads in Japan's hat-making inner circle is Ohko Ishida, daughter of famed milliner Akio Hirata, whose creations have graced the runways of Comme des Garcons, Yohji Yamamoto and Hanae Mori, among others.

Back in the late '60s, Hirata studied in Paris under the well-known French milliner Jean Barthet. It was there, in the French capital where Ishida was born, that the name Ohko -- which means "child of Europe" -- was bestowed on her.

At her atelier in Tokyo's upscale Nishi-Azabu, which she shares with her father, Ishida said that her serious induction into the world of hats came after she quit her job with a Japanese company and began working under him.

"I worked under my father for about 12 years. He didn't actually teach me, but I had a chance to watch him and look at what he made over a period of several years," she said. "Then, two years ago, I started my own brand, H.at, which stands for Hirata atelier."

Whereas her father's hats are custom-made, Ishida directs her creative energy toward something more casual -- a baseball cap or a floppy whatever-the-weather topping -- more in tune with today's young people in Japan.

"I wanted to make casual hats for daily wear," she said. "My father also creates some casual styles, but he prefers to make something more creative."

Her signature style: adaptable hats that can be worn different ways.

"I have hats that fold flat, which are easy to transport," she said. "I have hats in which the crown and the brim are joined by a piece of fabric and the crown pops up, revealing the different colored fabric in between. I also have other hats in which the brim can be changed according to the wearer's preference -- it can be worn down, worn up or pulled right back."

Even in the hat-making process, Ishida departs from her father's techniques -- he uses wooden blocks to mold hats onto -- creating instead a kind of skeleton on which to model the finished form.

For Ishida, the creation of a hat begins with the making of a template from layers of woven wood mesh, which is softened in water and then sewn together before being painted. "It takes two or three days to complete this process," Ishida said. It is only after the template is ready that the actual hat-making process can begin, she adds.

The fabrics she uses are mostly natural: lightweight ones -- cotton, linen braid and finely woven straw -- for summer; heavier ones -- felt or wool -- for winter.

The color palette is varied, but black is back. Ishida notes that the Japanese "like to wear black hats as it matches their hair color -- they seem to be more comfortable when wearing black."

In her latest collection, the colors range from dark -- browns, blues, blacks -- through neutral -- beige, ecru and pale gray -- and include patterns such as faux animal, tartan and plaid.

Making her own mark wasn't easy; there was always the pressure of public expectations that she'd follow in her father's footsteps. "In the beginning, people wanted me to make more decorative pieces, but right from the start I wanted to create more casual styles," she said.

"Now, two years later, people know what I can do and what I want to do, so there is really no pressure at all."

In fact, her creations got a warm reception when she participated in last October's "Fashion in Motion" event at the Victoria & Albert Museum in London. (Also showing was Tokyo-based fashion designer Yoshiko Nishimura, who is noted for her ethnic-inspired creations.)

That was Ishida's first time showing off her creativity overseas, and the results pleased her.

"Participating in a fashion event overseas was a good experience for my career, as it was something I'd not done before," she commented.

Since her London "debut," she has teamed up with her father for a joint show, sponsored by Saga Furs of Scandinavia, and last week, she held an intimate exhibition at the Tokyo atelier.

Although her international exposure is not at the same level as noted London milliner Philip Treacy, or 20th-century creators like Coco Chanel, Halston and Schiaparelli, Ishida is slowly making her mark in Japan.

Her creations are on sale at department stores in Tokyo and Yokohama, and at other specialty stores across the nation.

With price tags from 18,000 yen to 28,000 yen, Ishida's branded headgear is, in fashion terms, reasonable. But her most expensive piece, made from paper mesh interwoven with straw, carried a whopping 78,000 yen price tag.