{"product_id":"seiko-selection-hfb003j-jdm-open-heart-black-automatic-mens-watch-japan-made","title":"SEIKO SELECTION HFB003J JDM Open Heart Black Automatic Men's Watch Japan Made","description":"\u003cdiv class=\"text-base my-auto mx-auto [--thread-content-margin:var(--thread-content-margin-xs,calc(var(--spacing)*4))] @w-sm\/main:[--thread-content-margin:var(--thread-content-margin-sm,calc(var(--spacing)*6))] @w-lg\/main:[--thread-content-margin:var(--thread-content-margin-lg,calc(var(--spacing)*16))] px-(--thread-content-margin)\"\u003e\n\u003cdiv data-conversation-screenshot-content=\"\" class=\"[--thread-content-max-width:40rem] @w-lg\/main:[--thread-content-max-width:48rem] mx-auto max-w-(--thread-content-max-width) flex-1 group\/turn-messages focus-visible:outline-hidden relative flex w-full min-w-0 flex-col agent-turn\"\u003e\n\u003cdiv class=\"flex max-w-full flex-col gap-4 grow\"\u003e\n\u003cdiv data-message-author-role=\"assistant\" data-message-id=\"aba79353-58e2-4955-b961-0cb8ee5e1e7c\" dir=\"auto\" data-message-model-slug=\"gpt-5-5\" class=\"min-h-8 text-message relative flex w-full flex-col items-end gap-2 text-start break-words whitespace-normal outline-none keyboard-focused:focus-ring [.text-message+\u0026amp;]:mt-1\"\u003e\n\u003cdiv class=\"flex w-full flex-col gap-1 empty:hidden\"\u003e\n\u003cdiv class=\"markdown prose dark:prose-invert wrap-break-word w-full light markdown-new-styling\"\u003e\n\u003ch2 data-source-line=\"7-7\"\u003eDescription\u003c\/h2\u003e\n\u003cp data-source-line=\"9-9\"\u003eThe SEIKO SELECTION HFB003J is a men’s mechanical model from the S Series, designed to bring the appeal of Japanese automatic watchmaking into a clean and wearable everyday format. Its black dial, simple three-hand layout, and open-heart display create a modern and confident look while still highlighting the movement’s mechanical character beneath the dial.\u003c\/p\u003e\n\u003cp data-source-line=\"11-11\"\u003ePowered by Caliber 4R38, the watch uses a mechanical automatic movement with manual winding, offering approximately 41 hours of power reserve, 24 jewels, and a stop-seconds function. With 10 bar water resistance, Hardlex crystal, and a stainless steel bracelet, it combines practical daily durability with the tactile charm and visual interest of a traditional mechanical watch.\u003c\/p\u003e\n\u003cp data-source-line=\"13-13\"\u003eDesigned for buyers who want a more expressive alternative to a standard quartz dress watch, the HFB003J offers balanced comfort, clear legibility, and reliable everyday wearability. Within the SEIKO SELECTION lineup, it stands out as a Japan-made open-heart model that blends accessible mechanical value with a sharper black-dial presentation.\u003c\/p\u003e\n\u003ch2 data-source-line=\"15-15\"\u003eKey Specifications\u003c\/h2\u003e\n\u003cul data-source-line=\"17-32\"\u003e\n\u003cli data-source-line=\"17-17\"\u003eCase: 46.2 × 40.0 × 11.8 mm, 140.0 g, stainless steel case\u003c\/li\u003e\n\u003cli data-source-line=\"18-18\"\u003eBand: Stainless steel bracelet, one-push three-fold clasp\u003c\/li\u003e\n\u003cli data-source-line=\"19-19\"\u003eWater resistance: 10 bar\u003c\/li\u003e\n\u003cli data-source-line=\"20-20\"\u003eMovement: Caliber 4R38, mechanical automatic with manual winding\u003c\/li\u003e\n\u003cli data-source-line=\"21-21\"\u003ePower: Automatic, approximately 41 hours power reserve\u003c\/li\u003e\n\u003cli data-source-line=\"22-22\"\u003eAccuracy: +45 to -35 seconds per day\u003c\/li\u003e\n\u003cli data-source-line=\"23-23\"\u003eDisplay: Analog, black dial\u003c\/li\u003e\n\u003cli data-source-line=\"24-24\"\u003eFunctions: 3-hand display, open-heart display, stop-seconds function\u003c\/li\u003e\n\u003cli data-source-line=\"25-25\"\u003eSpecial features: 24 jewels, antimagnetic\u003c\/li\u003e\n\u003cli data-source-line=\"26-26\"\u003eGlass: Hardlex\u003c\/li\u003e\n\u003cli data-source-line=\"27-27\"\u003eOrigin: Japan Domestic Market (JDM)\u003c\/li\u003e\n\u003cli data-source-line=\"28-28\"\u003eMade in Japan: Confirmed\u003c\/li\u003e\n\u003cli data-source-line=\"29-29\"\u003eModel Code: HFB003J\u003c\/li\u003e\n\u003cli data-source-line=\"30-30\"\u003eJAN: 4954628473868\u003c\/li\u003e\n\u003cli data-source-line=\"31-32\"\u003eRelease date: June 5, 2026\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2 data-source-line=\"33-33\"\u003eKey Highlights\u003c\/h2\u003e\n\u003cp data-source-line=\"35-35\"\u003eThe HFB003J stands out through its black open-heart dial, giving it a stronger and more contemporary presence than lighter-dial mechanical models. The darker color scheme adds visual contrast and makes the visible movement feel more defined, while the overall design remains clean enough for everyday wear.\u003c\/p\u003e\n\u003cp data-source-line=\"37-37\"\u003eIts 4R38 automatic movement gives the watch authentic mechanical identity with hand-winding capability and dependable everyday usability. Rather than being positioned like a convenience-focused quartz model, this watch works best as an approachable introduction to genuine Japanese mechanical watchmaking.\u003c\/p\u003e\n\u003cp data-source-line=\"39-39\"\u003eOn the wrist, the 40 mm case gives the watch a balanced men’s size that feels easy to wear across casual, business-casual, and more polished settings. The stainless steel bracelet and black dial combination also make it especially versatile for buyers who prefer a more understated mechanical style.\u003c\/p\u003e\n\u003cp data-source-line=\"41-41\"\u003eWithin the SEIKO SELECTION S Series, the HFB003J is a strong JDM option for buyers seeking a Japan-made men’s automatic watch with an open-heart dial, darker styling, and solid entry-level mechanical appeal.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e","brand":"SEIKO","offers":[{"title":"Default Title","offer_id":48640708051199,"sku":"HFB003J","price":42500.0,"currency_code":"JPY","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0720\/0561\/5871\/files\/hfb003j_1.jpg?v=1780832753","url":"https:\/\/japanheartfulstore.com\/products\/seiko-selection-hfb003j-jdm-open-heart-black-automatic-mens-watch-japan-made","provider":"Japan Heartful Store","version":"1.0","type":"link"}