quattro's comprehensive overview of the Grand Seiko Tentagraph, the brand's inaugural mechanical chronograph, offers an essential guide for collectors. This post delves into the technical innovations of the Caliber 9SC5 and showcases the diverse aesthetic variants. Understanding the Tentagraph's design and engineering is crucial for appreciating Grand Seiko's entry into the mechanical chronograph space.
Introduced in
2023, the
Tentagraph was
Grand Seiko's
first ever mechanical chronograph.
The Tentagraph's name - “TEN-T-A-GRAPH” - describes the characteristics of the Caliber 9SC5 that powers this watch:
- TEN beats per second (36,000 vibrations per hour),
- Three days of power reserve (72 h),
The original “beasty” case - measuring 43.2 x 15.3 x 51.5 mm - was designed by Akira Yoshida.
The
caliber 9SC5, with its dual impulse escapement and twin barrels, was
engineered by
Kengo Ito.
The movement is
modular, with
9S base and a
chronograph module featuring a
column wheel and a
vertical clutch.
credit: Grand Seiko
Six variants have been made so far:
- Five belong to the Evolution 9 collection: SLGC001, SLGC002, SLGC004, SLGC006 & SLGC007.
- One belongs to the Sport collection and, more specifically, to the Tokyo Lion line: SLGC009.
Let's see them one by one.
A/ REF. SLGC001 (2023)
Blue dial with
Mt. Iwate texture, said to capture “the serene beauty of a snowy moonlit night over Mt. Iwate, as seen from the Grand Seiko Studio Shizukuishi, the home of Grand Seiko’s mechanical watchmaking”.
Black ceramic bezel.
High-intensity titanium case (grade 5), brushed with Zaratsu polished accents.
B/ REF. SLGC002 TOKUSENKAI LIMITED EDITION of 30 PIECES (2024)
Black dial with
Mt Iwate texture and
gold-toned subdials, depicting the
rising sun peeking out from behind Mount Iwate.
Black ceramic bezel.
18k pink gold case.
C/ REF. SLGC004 LIMITED EDITION of 60 PIECES (2024)
Black dial with
Mt Iwate texture and
gold-toned subdials, depicting the
rising sun peeking out from behind Mount Iwate.
Black ceramic bezel insert.
High-intensity titanium case (grade 5), brushed with Zaratsu polished accents - 18k pink gold bezel, crown and pushers.
Water resistance: 10 bar
credit: @watch.kamekichi
D/ REF. SLGC006 - LIMITED EDITION of 300 PIECES (2025)
New Mt. Iwate textured dial in
light copper-pink -
burgundy/brown and
copper chronograph
sub-dials.
Black ceramic bezel insert.
High-intensity titanium case (grade 5), brushed with Zaratsu polished accents - 18k pink gold bezel, crown and pushers.
Silvery ice-white and blue dial with Mt Iwate texture “honouring Mt. Iwate’s landscape in harsh winter.”
Black ceramic bezel.
High-intensity titanium case (grade 5), brushed with Zaratsu polished accents.
Water resistance: 10 bar
SLCG007 (left) - SLGC001 (center) - SLGC006 (right)
credit Monochrome & Hodinkee (three photos before last only) & @masaharu.me (last photo) F/ REF. SLGC009 - TOKYO LION (2025)
Tokyo Lion Brilliant Hard Titanium case (grade 5), brushed with Zaratsu polished accents measuring 43.0 x 15.6 x 50.0 mm.
Curved caseback.
Dark beige dial with pattern that takes inspiration from the mane of the lion as it waves in the wind. Black chronograph counters at 6 and 9 o'clock.
Diamond-cut indexes resembling the sharp claws of a lion.
Water resistance: 20 bar
credit: Monochrome (1-6) & Hodinkee
The Tentagraph could be considered Grand Seiko's Offshore, don't you think so?
Does this “beasty” chronograph appeal to you?
Personally, even if this isn't my kind of watches, I like the pink gold SLGC002 and the Tokyo Lion SLGC009.
Thanks fors looking.
Best, Emmanuel
BONUS - VIDEOS
Review of the SLCG001 by Tim Mosso
The SLGC002 by Commit Ginza
Review of the SLGC006 by Tim Mosso
Review of the SLGC007 by Time & Tide
Review of the Tokyo Lion SLGC009 by Time & Tide
About the Seiko Ref. SBGH315
The Grand Seiko SBGH315 is a contemporary mechanical timepiece from the brand's Heritage Collection, known for its classic design and high-beat movement. This model continues Grand Seiko's tradition of producing watches that combine precision engineering with understated elegance, appealing to collectors who appreciate refined horology without overt embellishment. It stands as a testament to the brand's commitment to the fundamental principles of watchmaking.
Powered by the Hi-Beat Caliber 9S85, the SBGH315 operates at 36,000 vibrations per hour, ensuring high accuracy. The watch features a stainless steel case, a sapphire crystal with anti-reflective coating, and a screw-down case back. Its dial is often characterized by intricate textures and meticulously finished hands and markers, reflecting Grand Seiko's renowned Zaratsu polishing technique.
For collectors, the SBGH315 represents a modern interpretation of Grand Seiko's historical high-beat movements. Its combination of a robust, high-frequency caliber and a timeless aesthetic makes it a sought-after piece. The model underscores Grand Seiko's position as a manufacture capable of producing movements and finishes comparable to leading Swiss brands.
Specifications
- Caliber
- 9S85
- Case
- Stainless Steel
- Diameter
- 39.5mm
- Dial
- White/Silver textured
- Water Resist.
- 100m
- Crystal
- Box-shaped sapphire with anti-reflective coating
About the Seiko Ref. SLGC009
The Grand Seiko Tentagraph SLGC009 marks a significant milestone as the brand's first mechanical chronograph, introduced within the Evolution 9 Collection. It embodies Grand Seiko's commitment to precision and practical innovation, developed and manufactured at the Shizukuishi facility, known for its mechanical watchmaking heritage. This model integrates advanced functionality with exquisite craftsmanship, reflecting decades of accumulated know-how.
At its core is the new Caliber 9SC5, a high-beat movement operating at 10 beats per second, based on the revolutionary Caliber 9SA5. This movement features a Dual Impulse Escapement for efficient energy transfer and two barrels, providing a 3-day power reserve even with the chronograph in operation. The Tentagraph undergoes an extended 20-day testing procedure, including three days of chronograph operation, to ensure it meets the Grand Seiko Standard of +5 to -3 seconds per day. The dial features a textured 'Mt. Iwate' pattern.
This reference is notable for its integrated vertical clutch and column wheel, ensuring precise chronograph operation and eliminating hand shudder. The overcoil's shape was optimized through extensive simulations for consistent performance. As a fully integrated manufacture, Grand Seiko maintains in-house control over every component, underscoring the technical prowess and dedication to horological excellence.
Specifications
- Caliber
- 9SC5
- Case
- Titanium
- Dial
- Blue (Mt. Iwate pattern)
- Water Resist.
- 10 bar
- Crystal
- Sapphire
