"The Wiz" is back where it belongs -- on stage.

A touring production of the black musicalization of "The Wizard of Oz" opened last night at the National Theatre, banishing memories of the sluggish and sodden screen version which was released last fall.

Where the filmmakers sweated over garish urban details, the playmakers relied on an urbane wit and the imagination of their audience. Where the filmmakers stretched for inspirational effect, the playmakers concentrated on giving their audience a good time.

Most important, the director of the play did not have to cast a 34-year-old ex-Supreme, Diana Ross, as little Dorothy.

The movie never recovered from the presence of Ross as Dorothy. Dorothy should be a strong child; Ross portrayed her as a weak adult.

Unfortunately, the current production does not come to terms with Dorothy either. Actress Renee Harris has a curiously infantile speaking voice. It's almost as if the Dorothy in "The Wizard of Oz" had been played by Shirley Temple instead of Judy Garland. But at least Harris looks the part. And she belts the songs instead of whimpering them as Ross did.

The Charlie Smalls/Luther Vandross score for "The Wiz" has been underrated, possibly because Quincy Jones padded and discofied it for the movie in order to accommodate more of the Ross whimpers. At the National it's restored to its original flavor: jaunty and jolly. Except for one superfluous song near the end of the show, the score -- and the entire show -- zip along joyfully, especially when compared to the pace of the movie.

The show's book, by William F. Brown, also makes a lot more sense than Joel Schumacher's screenplay. Dorothy's Kansas origins have been maintained, so the contrast between her placid home life and the Emerald City is real. The entire movie was set in New York City, and the boroughs looked remarkably alike.

In the play, the Wiz is the one who tells his friends what will happen "if you believe," befitting his role of a likable con man. In the movie this role of inspirational leader was assigned to Ross/Dorothy, for reasons which should be obvious. At the National, Kamal stops the show with his full-throated rendition of "If You Believe."

Similarly, George Faison's choreo-graphy for the show, using barely more than a dozen dancers, creates more excitement than all of Louis Johnson's hordes did in the movie

Except for a few technical problems which should be corrected after opening night, Geoffrey Holder's direction and costuming of the original production of "The Wiz" have been well maintained at the National.

Not even Diana Ross can kill "The Wiz."