The Orient RA-AC0028S (also referenced as RA-AC0028S10B / FAC00003W0) is an exquisite, vintage-inspired Japanese automatic dress timepiece from Orient’s world-renowned Classic Collection. Recognized globally among watch collectors and horology purists by its popular series nicknames—the "Bambino Open Heart", "Open Heart Bambino", or "Classic Open Heart"—this 40.5mm watch pairs a solid stainless steel case with a pristine white open-heart dial, an open aperture displaying the beating mechanical balance wheel at 9 o'clock, a retro domed mineral crystal, an exhibition see-through caseback, an in-house automatic movement, a 30-meter water resistance rating, and a rich brown genuine leather strap. Designed for modern gentlemen, executives, and mechanical watch enthusiasts who appreciate mid-century horological elegance combined with captivating movement visibility, it transitions effortlessly from business dress attire to formal evening occasions. The defining visual highlight of this RA-AC0028S reference is its captivating open-heart dial architecture at 9 o'clock, exposing the ticking balance wheel and escapement of Orient's in-house mechanical movement. Set beneath a signature vintage-styled domed mineral crystal, the white sunburst dial features elegant silver-tone hour markers, polished dauphine hands, and a clean perimeter track. The harmonic contrast between the crisp white dial face, mesmerizing open-heart window, silver accents, and rich brown leather strap delivers a sophisticated, poetic presence on the wrist. Beneath its artistic exterior, the watch is driven by Orient's reliable in-house Caliber F6T22 automatic mechanical movement with hand-winding and second-hand hacking capabilities. Operating at 21,600 vibrations per hour (3 Hz) across 22 jewels, this self-winding engine provides a 40-hour power reserve, offering smooth timekeeping performance visible both from the front open dial aperture and through the rear exhibition caseback. The case features classic executive dress proportions, measuring 40.5mm in case width with a case profile thickness of 12.0mm and a lug-to-lug distance of 46.8mm, ensuring an elegant and balanced fit under tailored shirt cuffs. Optical depth and vintage allure are enhanced by a signature domed mineral crystal. Designed for daily dress wear and light splash exposure, the solid stainless steel case incorporates an exhibition see-through screw caseback and a push-pull crown, achieving a certified 30-meter (3 bar / 100 ft) water resistance rating to protect against rain and hand washing. The timepiece comes completed on a supple brown genuine leather strap, secured by a solid stainless steel pin buckle clasp.
