Mounjad al-Sharif was a child then. On school holidays, he and his friends would come for a falafel sandwich, see a movie at the Automatique, and if they had money left, ride the tram home. Beirut’s long, bitter civil war killed Falafel Sahyoun. The store shut down in 1978, when the fighting got bad, and this part of the city became the front line of a divided city, where rival militias installed their snipers. The year the shop closed, Mustapha Sahyoun died. The tram line is long gone, and so too the Automatique. Falafel Sahyoun reopened in 1992, after the war ended — only to split in two in 2006, when Fuad Sahyoun broke away. He refuses to explain why, saying only that it was for his own “peace of mind.” Zuheir Sahyoun points to his brother’s wife. “Pillow murmuring,” Zuheir grumbles. “His woman.” “My business hasn’t been affected,” Zuheir quickly adds. “I have the same clients. More.” Zuheir’s shop bears a blue crown as its logo. Fuad’s has a yellow crown. At lunchtime, people drive up to one or the other. They take away bags of sandwiches, or they scarf them down sitting behind their steering wheels.

Zuheir insists that his is the original shop, and that he uses his father’s original recipe. He keeps a photo of his father behind the cash register. “Tell your driver, ‘Sahyoun,’ and he’ll know exactly where to bring you,” he says. Fuad dismisses the shop next door as “a fossil.” He hangs a photo of the singer Bryan Adams, eating his falafel sandwich. Across the street still stands an old office building, hollowed out by the war, its blown-out windows like mouths gaping at Falafel Sahyoun and Falafel Sahyoun.

Mr. Sharif, now a documentary filmmaker, still comes regularly, but only to Fuad’s shop. The falafels here are lighter and better for the stomach, he maintains, and worth an extra 500 Lebanese pounds. That is one difference between the shops. Zuheir’s regular sandwich costs 3,000 Lebanese pounds, equivalent to $2. Fuad’s is 3,500 Lebanese pounds. Fuad’s regular sandwich also has four falafel balls, while Zuheir’s has three. Would Mr. Sharif consider trying the other Falafel Sahyoun? “No. Why to risk?” he asks. He wipes a bit of sauce from the side of his lips and offers a morsel of free advice. “There are two things in life: When you want to eat — eat well,” he says. “When you want to enjoy — enjoy. Next week, I don’t know. I may be dead.” Youmna El Zein, visiting from Senegal with her four children, chooses Zuheir’s shop. Her Lebanese cousins have told her to come to this Sahyoun, she says. Samir Simon is less fussy. It’s just falafel, he says. “This place, that place — it doesn’t matter to me,” he says. “I go to whichever one. I don’t know the difference. It’s the same thing.” The brothers have one thing in common. They are both fond of philosophizing. “The most important thing in life is for the mind to be at peace,” Fuad muses. “If your mind’s not at peace, there’s no point to anything that you do.”

“Unity makes you stronger,” Zuheir says. When his brother first left, he used to wish they could get back together. “Now I’ve stopped wishing.” Lately, the fight has taken a bit of a nasty turn. Fuad has hung on his storefront an enlarged notice from the health department, penalizing Zuheir’s shop for a code violation. It has a red arrow pointing to Zuheir’s shop. “He plays dirty,” Zuheir says. What would he do to avenge his brother’s move? Nothing, Zuheir says and points his index finger up, toward heaven. Then he takes a drag from his cigarette.