Portuguese fado music is one of the most elusive styles you could ever hope to meet. Just when you think you have a handle on it, it challenges your hypothesis.

Often likened to blues, it sounds nothing like the 12-bar variety we know in North America. It's frequently compared to flamenco, but there's too much minor-key melancholy. That, too, is an oversimplification - there is happy fado music.

Fado sensation Mariza, who performs at the Spectrum tomorrow night, sings two such upbeat numbers on her second album, Fado Curvo, out on Tuesday. The title track celebrates the musical form itself, while Fiera de Castro (The Fair at Castro) is an extended joke about having too much fun at the fair.

"Fado is not always melancholic," said the 29-year-old singer. She breaks another rule on the disc when she occasionally drops the genre's standard instrumentation - Portuguese guitar, acoustic guitar and bass - for a few unorthodox touches, like the chamber arrangement in Retrato (Portrait) and the trumpet in O Deserto (The Desert).

"I'd never heard a fado with trumpet," she said with a laugh, explaining that she liked the sonic connection between the brass instrument and the Portuguese guitar.

Born in Mozambique, Mariza moved to Portugal with her family when she was a baby. That's where she first saw fado houses, clubs where the music is performed every night. It's also where she got acquainted with saudade - a kind of nostalgic longing that's as mysterious as fado itself, but somehow remains the genre's central theme.

The powerhouse vocalist started singing professionally when she was about 14, she said: "I learned to sing in the streets. With fado, you don't go to school or the conservatory to learn it. It was natural for me to sing."

Soon, though, she abandoned her native music for more well-worn styles, which she crooned in Portuguese clubs, bars and casinos.

"I had a trio. We used to sing bossa nova, blues, jazz," she said. "It was fantastic at that time, but I prefer now."

She credits the return to her first musical love for her modern-day happiness.

"I spent too much time trying to find myself with other types of music," she said. "I spent too much time running from fado because my friends said it was music for old people. I was a little bit ashamed to sing it. When I started singing it again, it was my passion.

"I feel like I've found myself. I could sing other things if someone invited me, but my records will always be fado," she said.

Mariza's first album, Fado Em Mim (Fado In Me), was released in 2001 and sold an impressive 100,000 copies worldwide. Last year, she got a standing ovation from a decidedly hip-hop crowd when she opened for Lauryn Hill at the Hollywood Bowl.

That kind of exposure is designed to make her music approachable to a mainstream crowd, even while she walks the tightrope of remaining true to its traditional spirit. In the end, it's the lyrics - not the sounds - that remain the most important element for her.

"I need to identify with the words. The music will only have meaning if the poem makes sense to me - if I feel connected with the words," she said.

Montreal gets to sample the whole package live tomorrow night when Mariza delivers highlights from both her discs, accompanied by a backup trio. Bring your emotion.

"When you cut yourself, your skin is open. Normally, you have a cut in your soul, too," she said. That's the kind of injury her singing is designed to heal, she said. "It hurts, but at the same time it feels very good. That's the feeling."

Mariza, with Intakto, appears tomorrow night at 8:30 at the Spectrum, 318 Ste. Catherine St. W. Tickets cost $30, plus taxes and service charge, and are available at Admission, call (514) 790-1245 or go to www.admission.com

bperusse@thegazette.canwest.com