Rihanna is just who she is

Who exactly is Rihanna? This 19-year-old singer from Barbados is responsible for what might be the year’s biggest hit, “Umbrella,” yet since she first showed up on pop radio in 2005, Rihanna has resisted the ready-made characterizations that typically accompany such an ascent.

“Pon De Replay,” her first single, played up her Caribbean roots with an effervescent dance hall beat, but “S.O.S.” portrayed her as a disco-punk princess, while “Unfaithful” did the grown-up piano-ballad thing. At the MTV Video Music Awards in September, Rihanna joined emo-rock band Fall Out Boy for a performance of her sassy new-wave tune “Shut Up and Drive.” And though her current album is called “Good Girl Gone Bad,” “Umbrella” makes a promise of unwavering devotion.

The singer reveled in the contradictions Tuesday at the House of Blues in West Hollywood, showing more interest in demonstrating her range than her concentration. Unlike peers such as Beyonce, who works hard to present an image of airtight self-assuredness, Rihanna seems up for anything; she’s as unclear about who she is as we are, and that gives her music a spark that feels remarkably true to the 19-year-old’s experience.

The appealing disarray began with her six-piece band, which appeared to include two members of My Chemical Romance, two members of the Roots and two of the Pussycat Dolls.

Looking Goth-girl chic in a black tutu and bondage-inspired heels, Rihanna opened her hourlong set with a scrappy garage-pop take on “Pon De Replay” that offered a sign that she’s been looking to “Rhythm Nation”-era Janet Jackson for stylistic cues lately. There were others, including a hair-metal duel between her keyboardist and guitarist during “Let Me,” from 2005’s “Music of the Sun,” and a reggae-rock breakdown in “Kisses Don’t Lie,” from last year’s “A Girl Like Me.”

Tuesday’s show wasn’t all about rock, though: Whipping around a pink feather boa, Rihanna gave “S.O.S.” a post-”Chicago” Broadway makeover, but wisely made no attempt to overpower the tune’s signature riff, which comes from Soft Cell’s synth-pop classic “Tainted Love.” And a version of “Is This Love” by Bob Marley -- “one of my favorite artists of all time,” Rihanna said -- throbbed with a mellow island-life vibe.

Not every gesture connected. In “Hate That I Love You,” her new single, Rihanna emphasized her snooze-worthy goody-two-shoes side. Later, she overdid “Unfaithful,” a soap-operatic number that doesn’t require melisma or moody blue lighting.

Inevitably, the end of the show brought “Umbrella,” which Rihanna introduced with a spare guitar-and-voice verse that seemed to acknowledge Marie Digby’s home-recorded YouTube version of the hit. Then the track’s booming beat kicked in, and Rihanna exercised the unique brand of stardom she’s still figuring out.