When Yukiko Ishida walks on a stage, standing at 4-foot, 11 1/4 inches tall, her job is to make sure the audience is so impressed with her powerful voice that they're not distracted by her petite frame.

"I want to command the stage, so I can communicate with the audience," said Ishida, a coloratura soprano and a music professor at Neumann College in Aston, where she has taught for 15 years and is known as Dr. Yuki to students.

Her size has limited theatrical opportunities in opera companies. But that voice - which she treats like a musical instrument - carries her through concerts, allows her to win international awards, and helps her make connections between her native country, Japan, and the United States.

"I consider her a bit of Japanese-American ambassador," said Philadelphia pianist David Lofton, who met Ishida shortly after she came to the United States to study voice at Temple University.

"She always manages to mix the different kinds of music and do such a wonderful presentation with it."

In performances, she combines works by Japanese, American, Austrian, French, Italian and other composers. And she is doing academic research on a musical program left behind when Commodore Matthew C. Perry brought several U.S. Navy ships to Japan in 1853 and 1854.

Ishida will perform with two other members of the East West Ensemble at 4 p.m. next Sunday at Union United Methodist Church in Havertown, where she is the minister of music. Proceeds will benefit the Asian American Women's Coalition's Cecilia Moy Yep Scholarship Fund.

At 6 the next morning, she'll head to Tokyo, where she'll perform and present lectures. Ishida, who declined to reveal her age, lives in Wynnewood with her husband, but the rest of her family still lives in her native country.

She was born in Kumamoto, Japan, and received her bachelor's degree in music in Tokyo. She studied in London before working toward her master's degree as a Temple student. Whenever she got too homesick, she listened to

Madama Butterfly

, an Italian opera about Japan.

She continued her education, receiving a doctorate in musical arts from the now-closed Combs College of Music in Philadelphia. About six months after graduation, she started teaching at Neumann.

Along the way, she has performed at recitals in concert tours and lecture series in France, Germany, Italy, and Japan and throughout the United States. She also has appeared as a soloist with the Czech National Symphony Orchestra in Prague, the National Philharmonic near Washington, and others.

She has won numerous awards and competitions, including the Vocal Solo Performance Award from the Beethoven Piano Society of Europe in September.

About 25 percent of her singing preparation involves vocal cord exercises. The other 75 percent of the time, she learns about composers, and studies, translates and memorizes songs.

"It's like a piano. I have to rest it," Ishida said of her voice.

Before shows, she drinks warm water, and during the spring, she avoids spending too much time under trees, because of a pollen allergy.

For the past three years, Lauren Gallagher, a 22-year-old Neumann senior from Parkesburg, Chester County, has been Ishida's assistant for concerts near Philadelphia, or a few hours' drive away.

"She is a phenomenal person, and I just consider her one of my best friends," said Gallagher, an English major with a double minor in music and criminal justice. "She's always there for me."

Backstage, at a faculty concert last month at Neumann's Meagher Theatre, Gallagher was there for Ishida, doing a little bit of everything.

"Basically keeping her calm and relaxed, because she gets tense," said Gallagher, who helped sort music, apply makeup, organize gear and change outfits.

Ishida wore two gowns at the Neumann performance, both with the same floral pattern, but in different colors. For Alessandro Scarlatti's "Sono unite a tormentarmi," Ishida wore a pinkish orange gown. And for Wolfgang Amadeus Mozart's "L'amero, Saro Costante" from

Il Re Pastore

, she wore a bluish green one.

When Ishida pulled a shoulder muscle about two hours before the show, Gallagher grabbed an athletic trainer for help. Before going onstage, Ishida worried that her movement would be so limited that she would look like a robot.

"Once I started to sing, I forgot," Ishida said.

The only difficult part came between songs, when she talked about a student who would head to Iraq as a Marine in the fall, after he graduated from Neumann.

"I wasn't sure if I should say it," Ishida said. She worried that she might lose control of her emotions. But once she started singing, she was back in command. It was worth the risk, too.

"I love each of my students," Ishida said. "Because I don't have family here, the students are like my family."

If You Go

The East West Ensemble will perform at 4 p.m. next Sunday at the Union United Methodist Church, 200 Brookline Blvd., Havertown. Admission is free, but donations are encouraged. Proceeds will benefit the Asian American Women's Coalition's Cecilia Moy Yep Scholarship Fund.

For more information, call 610-642-1328.