{"reference": {"slug": "greubel-forsey-quadruple-tourbillon-platinum", "brand": "Greubel Forsey", "ref": "Quadruple Tourbillon", "model": "Quadruple Tourbillon Secret", "case_material": "Platinum", "url": "https://mostexpensivewatches.net/reference/greubel-forsey-quadruple-tourbillon-platinum", "description": "The Greubel Forsey Quadruple Tourbillon Secret in platinum was introduced in 2012 as a limited edition of eight pieces, following the original 2008 Quadruple Tourbillon. This reference utilizes the caliber GF02s, which features four tourbillons coupled by a spherical differential. Two double-tourbillon systems operate independently; each consists of an inner cage inclined at 30 degrees rotating every minute, housed within an outer cage rotating every four minutes. Unlike the open-dial versions, the Secret variant conceals the mechanism beneath a solid gold dial, displaying only the power reserve, small seconds, and dual tourbillon rotation indicators. On the secondary market, these timepieces typically command prices between $350,000 and $500,000 depending on provenance. A notable auction result occurred in 2021 when a platinum example sold for approximately $475,000, reflecting its rarity and the technical complexity of the differential-driven movement architecture."}, "listing_stats": {"count": 0, "median": 0, "low": 0, "high": 0}, "listings": [], "auction_lots": [{"slug": "greubel-forsey-quadruple-tourbillon-2018", "brand": "Greubel Forsey", "reference": "Quadruple Tourbillon", "model": "Quadruple Tourbillon", "case_material": "Platinum", "hammer_usd": 356687, "year_sold": 2018, "venue": "Phillips Hong Kong", "lot_summary": "An impressive feat of engineering featuring four tourbillons connected by a spherical differential, housed in an asymmetrical platinum case.", "source_url": "https://www.phillips.com/detail/greubel-forsey/HK080118/832", "provenance": "ai_generated_grounded", "url": "https://mostexpensivewatches.net/auctions/greubel-forsey-quadruple-tourbillon-2018"}]}