A tender, sincere Bill MurrayIn Sofia Coppola's "Lost in Translation," he finds his role of a lifetime.

Sleepless in Shinjuku, Tokyo's swarming business district, two jet-lagged Americans first cross paths, then circuits and, finally, their hearts, in Sofia Coppola's dreamy Lost in Translation.

This year's must-see film stars an improbably tender Bill Murray as Bob Harris, a 50ish actor in Japan to endorse Suntory whiskey. In this role of a lifetime Murray strips himself of his habitual helmet and armor of irony. See Bob, unaccustomed to the lightness of being.

Away from his customary routine Bob considers that, yes, armor might protect him from attack, but it also makes him impervious to feelings, even the good ones.

Disarmed, he is suddenly vulnerable to the prickly charms of Charlotte (Scarlett Johansson), like Bob an American visitor battling dislocation, existential panic, sleep deprivation and spousal indifference. Despite a 25-year age gap, sarcastic Charlotte is drawn to the droll actor she runs into everywhere in the swanky Park Hyatt, an oasis amid the din of Tokyo's entertainment district.

It's fitting that the man experiencing midlife crisis and the woman experiencing quarter-life crisis help guide each other through this rough patch.

For Charlotte, an Ivy League overachiever paralyzed by the realization that she has accomplished very little, Bob supplies firm encouragement. To Bob, Charlotte provides an infusion of youthful energy and curiosity.

Theirs is a gallant flirtation tinged with laughter and melancholy. Much as they delight in each other's company, the shadows on this sunny sojourn are cast by far-off spouses with whom they cannot connect. Bob knows something about marriage that comparative newlywed Charlotte does not. He knows, as novelist Vicki Baum dryly observed of wedlock, that "[It] demands the finest arts of insincerity possible between two human beings."

The brilliance of Murray's acting, which draws on his patented persona of halfhearted hypocrite, is Bob's rediscovery of sincerity. Murray struck this chord first in Groundhog Day and again in Rushmore. But his sincerity bear hug is ineffably moving.

Coppola's keenly observed film is many things at once: a quasi-romantic comedy, a lyrical travelogue, and a meditation upon how the modern devices meant to connect us - faxes, cell phones, snapshots - distance us instead.

Initially it seems that Coppola's panoramic shots of Tokyo (seen through picture windows of luxury hotel rooms) belong to the travelogue and the loving close-ups of her stars belong to the chaste romance.

Soon background and foreground merge with an effortless charm. Seen through their windows, Tokyo is a widescreen movie - a neon hallucination, spectacular but impenetrable.

But when Bob and Charlotte venture out to experience the city, separately and together, they begin to penetrate the culture. It's so different in the protocols of urban planning, of social deference and gift-giving. But it's so much the same in its arcades (Pachinko instead of video) and its club scene, which speak the Esperanto of global youth culture.

The one awkwardness in this supremely graceful film involves condescending jokes about why, in their attempts to speak English, the Japanese mix up their l's and r's. At least in this film the Japanese try to speak English, where the reverse is not true.

More representative of the movie's tone is a sequence in which Charlotte, wandering through the hotel meeting rooms, exits a shrill news conference for an American action movie and enters a room where women serenely practice the art of ikebana, traditional flower arranging. Coppola makes the contrast between the hyperbole of American commercialism and the harmony of Japanese art as lyrical as a haiku.

Coppola, 32, is a year younger than her father was when he released The Godfather. Although Translation is only her second feature, she already shows signs of being a sensei, as the Japanese call a master.

Contact movie critic Carrie Rickey at 215-854-5402 or crickey@phillynews.com.

Lost in Translation **** (out of four stars)

Produced by Ross Katz and Sofia Coppola, written and directed by Sofia Coppola, photography by Lance Acord, music by Brian Reitzell, distributed by Focus Features.

Running time: 1 hour, 45 mins.

Charlotte. . . Scarlett Johansson

Bob Harris. . . Bill Murray

Charlie Brown. . . Fumihiro Hayashi

Kelly. . . Anna Faris

John. . . Giovanni Ribisi

Parent's guide: R (lap dancers, sexual candor)

Playing at: Ritz Five and Ritz Sixteen/NJ