Bell & Ross is celebrating the 10th anniversary of the BR 01, its strikingly square watch. So the brand — founded in 1992 — planned a birthday party and produced 500 special-edition models.In black ceramic and stamped with a 10th-anniversary logo, the watch shows the company’s aeronautical inspiration: “From the cockpit to the wrist.” The face has the same numbering style as aviation counters; the strap is rubber, and the four functional screws at the corners of the 46-millimeter case ensure water resistance to a depth of 100 meters.

“As a young house, we have always sought to differentiate ourselves,” said Bruno Belamich, creative director and co-founder of Bell & Ross. “The square shape of the BR 01 prompts strong reactions: Some people love it, others find it ugly, but that’s a good sign.”

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“Watches have become mere accessories,” he added. “Yet at Bell & Ross, our challenge is to take an extremely utilitarian approach, and to thrive on it.”

“At the end of the line, some of our most successful models are bijou versions of functional design,” he said. Yet the French Air Force and Germany’s Spacelab mission, among others, also have ordered watches from Bell & Ross, which has its manufacturing site Switzerland.

The house has also introduced a limited- edition BR-X1 Chronograph Tourbillon. Only 40 will be made, in titanium or rose gold, with or without diamonds. It includes a chronograph tourbillon of 282 parts and 35 rubies, with skeletonized movement.

“Designing such a superlative sports watch, when you think of it, is a bit of a folly,” Mr. Belamich said. “But at Bell & Ross, we constantly innovate to address these two demands: extreme simplicity and extreme sophistication.”