Royal Oak Ref. 56175ST “Yves Klein”

Initially developed as an accessibly-priced, smaller-sized, men's Royal Oak, the reference 56175ST is a 33mm quartz-powered variant of Gérald Genta’s original design. This particular example is among the rarest iterations, distinguished by its striking blue dial, often referred to by collectors as “Yves Klein.” The vivid, electric blue tone closely echoes the signature shade favored by the French artist Yves Klein during the 1960s. Deeply inspired by the open sky, Klein dedicated himself to refining this intense ultramarine hue, believing it best expressed the feeling of limitless space. His artistic work eventually revolved around this singular color, which was later patented as International Klein Blue (IKB).

This reference is built around the ultra-thin Caliber 2612 — a movement measuring just 1.9mm in thickness. Thanks to this, the entire watch is impressively slim, with a case thickness of only 6mm. Though not always a focal point for collectors, Ref. 56175ST evolved through multiple generations and holds subtle distinctions that merit attention. Early versions showcased the classic Royal Oak aesthetics, including the fine ‘Petite Tapisserie’ dial pattern and the original small AP logo. As the brand refreshed its visual identity, later pieces from the second generation adopted the modernized AP logo while retaining the finely patterned dial. In the third generation, design updates included a shift to the larger ‘Grande Tapisserie’ motif, abbreviated hour markers, and the addition of numerical five-minute indices.

“Yves Klein” dials are extremely scarce, appearing in only a fraction of Royal Oak production, and carry a notable premium to collectors.