Bianchet Tourbillon

Bianchet Tourbillon is the Swiss brand Bianchet's collection of tourbillons: skeletonised movements in tonneau cases whose geometry is based on the golden ratio, 1.618. The Openwork and Flying Tourbillon Sport GMT models use calibre B1.618 — in the Sport GMT it is the B1.618 GMT version — and come in 43 mm cases of carbon composite; the brand's B1.618 series also has its own page. The Ultrafino has a 40 mm case of transparent sapphire crystal through which the movement can be seen from every angle.

Within the collection the choice comes down to case and functions. Some carbon versions are highlighted with coloured accents on the case band, gaskets and strap. Sapphire is for those who want complete transparency. The Openwork models — the Carbon Tourbillon Openwork Unique Piece and the Tourbillon Openwork Carbon Blue — are hand-wound. The Flying Tourbillon Sport GMT adds a second time zone to its flying tourbillon. Models with calibre B1.618 have a 105-hour power reserve.

Some versions are rare. The Carbon Tourbillon Openwork Unique Piece exists as a single example. The Tourbillon Openwork Carbon Blue is a limited series of 21 pieces, each with its own serial number. The Flying Tourbillon Sport GMT and Ultrafino pieces date from 2025.