Seiko Mechanical Semi-Skeleton (open heart) References SARL001, SARL003 and SARL004

Introduced in 2007 as the part of Seiko Mechanical Series, these Semi-Skeleton timepieces (SARL001, SARL003 and SARL004) stand out with the open-heart display on the dials.

Each of them is hand-made at the Shizukuishi Watch Studio (Shizukuishi-cho, Iwate-gun, Iwate Prefecture) within Morioka Seiko Instruments Co., Ltd., where mechanical watch parts are manufactured and assembled.

Seiko Mechanical Semi-Skeleton Watch SARL004

Through a circular dial-opening, you can see the beating heart of the watch, the escapement mechanism, including the balance, pallet, and escape wheel. In addition, the window is surrounded by a metal frame that is pinned at three points, giving it a sophisticated finish.

Seiko Mechanical Semi-Skeleton Watch SARL001
Reference SARL001

The movement beating inside the each Open Heart model is Seiko Caliber 8L38. This 26 jewel automatic movement offers a power reserve of approximately 50 hours. The three-pronged bridge, which supports the balance that governs the precision of a mechanical watch from external shocks, is painstakingly hand-crafted with a traditional boxwood pattern. The watch features a see-through case-back structure that allows you to admire the movement.

Seiko Mechanical Semi-Skeleton Watch SARL003
Reference SARL003

The 41.0mm case is made of stainless steel. Seiko’s traditional polishing technique, Zaratsu polishing, is applied to the slant of the case to give it a sharp, distortion-free mirror finish. The SARL004 model features pink gold finished bezel while SARL001 and SARL003 have steel bezels. Both the front and case-back glasses are in sapphire crystal.

Technical details

Model: Seiko Mechanical Series Semi-skeleton

SARL001: Black dial, stainless steel case, and stainless steel bracelet
SARL003: Navy blue dial, stainless steel case, dark blue crocodile strap
SARL004: Tea (brown) dial, stainless steel, pink gold color plated bezel, brown crocodile strap

Stainless steel
Case diameter: 41.0mm
Thickness: 12.7mm
Dual curved sapphire crystal glass with non-reflective coating
Case-back: Sapphire glass see-through back
Water resistant to 10 bar
Magnetic resistance: Antimagnetic watch (JIS Anti-magnetic watch type 1)

Black, Navy Blue or Brown
Hands and indexes with Lumibright

Caliber 8L38
Mechanical movement with automatic winding (with manual winding)
Time accuracy: +15 seconds to -10 seconds per day
Frequency: 8 vibrations/second
26 jewels
Diameter: 28.4mm
Thickness: 5.3mm
Power reserve: Approx. 50 hours
Second hand stop function

Retail price in Japan
210,000 yen (200,000 yen without tax)