{"reference": {"slug": "iwc-431", "brand": "IWC", "ref": "431", "model": "B-UHR (Grosse Fliegeruhr)", "case_material": "Stainless Steel", "provenance": "extracted_from_auction_comps", "url": "https://mostexpensivewatches.net/reference/iwc-431", "description": "The IWC B-Uhr Reference 431, also known as the Grosse Fliegeruhr, was produced in 1940 for the German Luftwaffe. Collectors value this reference for its historical role as one of the five original manufacturers of the Beobachtungsuhr. The watch features a 55mm matte-finished staybrite stainless steel case designed for wear over flight suits and utilizes the Calibre 52 T.S.C. movement, which includes a central hacking seconds function for precise synchronization. The dial follows the Type A configuration with a luminous triangle and two dots at twelve o'clock. Approximately 1,000 units were manufactured, making it a rare military instrument. On the secondary market, these watches typically command prices in the mid-to-high five-figure range, often between $30,000 and $60,000 depending on condition. A notable auction result occurred at Christie’s in 2015, where a well-preserved example realized approximately $56,000."}, "listing_stats": {"count": 0, "median": 0, "low": 0, "high": 0}, "listings": [], "auction_lots": [{"slug": "iwc-431-2015", "brand": "IWC", "reference": "431", "model": "B-UHR (Grosse Fliegeruhr)", "case_material": "Stainless Steel", "hammer_usd": 18800, "year_sold": 2015, "venue": "Phillips Geneva", "lot_summary": "An oversized 55mm pilot's watch produced in 1940 for the Luftwaffe, featuring the large caliber 52 movement.", "source_url": "https://www.phillips.com/detail/iwc/CH080215/142", "provenance": "ai_generated_grounded", "url": "https://mostexpensivewatches.net/auctions/iwc-431-2015"}]}