Released in 1999, just a year after Shakespeare in Love won an Oscar and mined the creation of Romeo and Juliet for maximum romance and whimsy, it wouldn’t have been surprising to see Leigh’s first period piece indulge in some of that film’s sweep and charm. But the director uses Gilbert and Sullivan’s conception of The Mikado, their greatest opera, as a sort of rebuke to Shakespeare’s fanciful romance, bringing his trademark realism to the height of the British Empire. Topsy-Turvy posits whimsy as (for better or worse) a crowd-pleasing fabrication and the theater as a grueling exercise in pluralism.

It’s 1884 in London and Gilbert and Sullivan are in a rut. Reviews of their latest opera, Princess Ida, are lukewarm, suggesting that the librettist W.S. Gilbert is repeating himself, always hinging his works on magic potions and spells. The cantankerous, willful Gilbert (Jim Broadbent) nevertheless begins work on his next piece, a similar story set in a different exotic location. His partner, composer Arthur Sullivan (Allan Corduner), plays the foil to the neurotic, self-absorbed wordsmith, threatening to leave the theater to compose a great symphony. But the pair's employer, the Savoy Theatre, needs a new play to make up for Ida's failing returns, bringing the conflict to a head.

In one of the film’s many ingenious structural sleights of hand, Leigh essentially abandons the dispute right there, and skips to Gilbert’s “Eureka!” moment. The writer finds his muse in the unlikely form of a samurai sword, which he purchases at an exposition of Japanese culture. At home, the sword literally falls at his feet and an idea, melding Gilbert’s predilection for “topsy-turvydom” and Sullivan’s need to write music portraying “genuine human emotion,” is born.

Broadbent portrays the writer’s moment of realization like the world’s slowest light bulb turning on, and Leigh fittingly makes this the film’s only comment on the joy of creation, eschewing the sentimentality of frantic writing and the pair making amends. These omissions make it clear that the “creative process” isn’t as romantic as they’re usually made out to be, suggesting it’s the grinding work of daily rehearsals and incessant compromise that make stage magic.

Leigh’s expansive rehearsal scenes address all aspects of the performance. Gilbert teaches actors how to pronounce “corroborative” and recruits Japanese visitors to show his actresses how to “walk downstage in the Japanese manner;” both male and female actors object after learning they can’t wear corsets onstage (“Japanese ladies are most shapeless”); we even watch ushers silently inspecting the underside of each chair in the theater.

The wordplay is dense and delightful, but it’s the tapestry of teamwork and minutiae that makes Topsy-Turvy one of the great films about the artistic process. It’s less about the excitement of creation than the fact that working in the theater demands sacrifices. A wealth of period concerns — heroin use, poverty, sexual politics, cultural appropriation, British imperialism — are hinted at but not pondered on, and scenes of the finished work (interspersed with the rehearsals) are stirring and gratifying.

Even after The Mikado is hailed as Gilbert and Sullivan’s greatest work, Leigh subverts a happy ending, with Gilbert’s memorable moan, “There’s something inherently disappointing about success.”

Christopher Gray can be reached at cgray@thephoenix.com .