Grand Seiko Heritage Collection Series 9 SLGH005 is equipped with a high-frequency 9SA5 movement, inspired by the white birch trees that grow near Shizukuishi's studio. Our test examines how nature and watchmaking craftsmanship are reflected in this latest work.
The word "birch" can be traced back to an Indo-European language, meaning shiny or gleaming-describing the white bark of this unique deciduous tree. Although our test watch Grand Seiko SLGH005 does not have any luminous objects on the dial, it will produce the sparkling light specially created for this watch regardless of day or night. View it from any angle, the prominent application marks always capture the light, and even the smallest movement of the wrist will reflect it onto the next polished surface. The reflection does not affect the legibility during the day, because the deep grooves, highly polished markings and hands are large and clear enough to create a sharp contrast with the matte dial background. The delicate texture of the dial implies birch bark, with large and small grooves, higher ridges and thin strips peeling off the trunk.
In a figurative sense, the bark at the 3 o'clock position where the large silver rim date opening is located has been stripped a bit. The black and white color scheme of the date display complements the overall appearance of the birch. The date will advance in an instant-it happened on our test watch, about 7 minutes after midnight. The position of the second pull crown can be adjusted quickly, and the outermost pull position can be used to move the pointer forward or backward without damaging the movement in any way.
The only color on the basic dial of the new-generation movement is the slender blue second hand. Thanks to the high frequency of the 9SA5 movement, the second hand advances 10 steps per second. The delicate tip slides over the edge of the narrow dial with seconds and minutes markers. Pulling the large grooved crown fully to the outside position stops the watch for precise second setting-this is an indispensable feature because of the latest Grand Seiko standard of SLGH005 equipped with Hi-Beat Calibre 9SA5 The specifications may only apply to a maximum increase of 5 seconds or a decrease of 3 seconds per day. Our test watch meets this strict standard. When we tested it on an electronic timing machine, it increased by 2.5 to 4.1 seconds per day. The watch runs even better in real life, with a deviation of only about 1 second per day.
Grand Seiko developed the Hi-Beat self-winding movement 9SA5, which was first launched in March 2020 and was completely developed by internal staff in nine years. According to the company, it forms the basis of a new generation of Grand Seiko mechanical watches. The movement was first used in gold SLGH002, limited to 100 pieces, and priced at US$43,000. It is closely followed by the limited edition SLGH003 for the 60th anniversary of Fine Steel Seiko, limited to 1,000 pieces and priced at US$9,700. Our test watch SLGH005 is the first unlimited production watch with a new movement. It can be purchased at Grand Seiko boutiques and select watch dealers for $9,100. This is still an ambitious price, because the Master Chronometer with a stainless steel bracelet is priced at $5,700, while the Oystersteel Rolex Datejust 36 with a Jubilee bracelet is priced at $7,300.
High frequency and extended power require new technology Calibre 9SA5 integrates a number of three key developments that have been patented or are pending: the new double-pulse escapement, the free-spring Grand Seiko balance, and the level of the barrel and gear train Layout. These mechanisms are designed to ensure accuracy, durability and aesthetics.
In order to achieve the highest level of accuracy, Grand Seiko decided to start developing a high-jumping core with a speed of 36,000 vph-the company's philosophy since 1968 has been its extremely accurate Hi-Beat movement. At the same time, a modern power reserve of 80 hours is also a goal. Since the balance wheel frequency and long power reserve require more energy, and the new movement is designed to be 15% thinner than the previous Grand Seiko high-jumping movement, it is necessary to redesign and apply new technology from the ground up. Due to the desire to reduce the height of the movement, two barrels arranged in sequence were used to replace one large barrel. Because of this, and the horizontal arrangement of the gear train, the 9SA5 is now 15% thinner than the previous Grand Seiko movement.
The free balance spring precision regulator specially developed for the 9SA5 movement also supports high precision. There are four weighted screws on its balance wheel, which is a new product of Grand Seiko. The lag screws are located in the grooves (to prevent loosening) of the four insertion parts of the balance wheel (to minimize air turbulence).
The balance wheel is more resistant to shock and friction and shows a higher accuracy rate. Contributing to this is the special Grand Seiko hairspring, which has a special upper ring made of a unique alloy called Spron. Its tailor-made design improves isochronism, that is, uniform oscillation. The knowledge of the positive influence of the upper coil on the speed of the timepiece can be traced back to Abraham-Louis Breguet (Abraham-Louis Breguet).
Double pulse makes the power transmission effective. When the power is transmitted to the balance wheel through the new double pulse escapement, the escape wheel directly transmits the power to the balance wheel in one direction, which increases the efficiency of the entire system by 20% and reduces the corresponding Energy demand. In the other direction, power is transmitted through the pallet fork, just like a traditional escapement. This design is similar to the Omega coaxial escapement, but it is much more complicated. Today, these designs can only be produced using modern manufacturing techniques, such as the micro-electromechanical systems (MEMS) that Grand Seiko has used in early movements. This process is adapted from microchip manufacturing and is used to produce the escape wheel and pallet fork of 9SA5.
Beautiful and fine details, even on hidden parts, MEMS allows the lightweight construction of the escape wheel and pallet fork, which saves more energy and contributes to a higher power reserve. With this manufacturing method, the mold is first etched, and then the metal is deposited into the mold using an electroplating process. This also reflects another specialty of Grand Seiko: tiny grooves in the teeth of the escape wheel can increase the amount of oil at the point of failure.
Although these features cannot be seen with the naked eye through the sapphire back of the watch, the high frequency of the Calibre 9SA5 makes them very clear. Only when the watch is stopped, its extraordinary geometry will be revealed, with embedded parts and angular screw heads. A sturdy balance bridge instead of a single-sided balance bridge provides stability-a structural feature that is gaining popularity among Swiss watchmakers such as Rolex, Tudor and Panerai.
The view also includes the generously hollowed out two-way pendulum and the exposed perforated bridge structure. This reveals a large part of the mechanism, such as the two barrels under the arch bridge. Numerous decorative finishes such as stripes, pearl patterns, sunburst finishes, polished screw heads, beveled edges, and exquisite carvings on the winding rotor require time and a lot of effort. Even the hidden surfaces of the parts are covered with various decorations, such as the main bridge with the initials of Grand Seiko engraved on the barrel splint, screw-in crown and folding clasp.
The excellent overall appearance and realistic buckle complete the very attractive three-link bracelet, which is connected to the case by a fixed connection. It narrows towards the buckle with the turnbuckle, and the length of the bracelet can be adjusted. Its beveled edges, polished sides and brushed upper surface are well done. It continues the appearance of a powerful case, with a mirror-like Zaratsu finish on the narrow bezel, and brushed finishes on both sides of the wide case.
Grand Seiko designated the overall appearance of this watch as its Series 9 design. It will become an important part of the heritage collection in the next few years. Grand Seiko has always stayed true to the style established by 44GS in 1967. Although impressive, Grand Seiko SLGH005 exudes harmony, calm and stability-just like walking in the birch forest.
Specifications: Manufacturer: Morioka Seiko Instruments Inc., 61-1, Itabashi, Shizukuishicho, Iwate-gun, Japan Reference Number: SLGH005 Functions: hours, minutes, seconds, date Movement: internal 9SA5 movement, automatic, 36,000 vph, 47 jewels, certified by the Grand Seiko standard (-3 to 5 seconds/day, tested in 6 positions, 17 days), four adjusting screws on the balance wheel, Spron 610 hairspring with upper ring, Diachock shock absorber , Double-pulse escapement, 80-hour power reserve, diameter = 31.6 mm, height = 5.18 mm Case: stainless steel, box-shaped sapphire crystal, anti-reflective coating on both sides (top), sapphire back, waterproof Bracelet and buckle with a depth of 100 meters: stainless steel single-sided folding clasp bracelet with push buttons Score results (every 24 hours deviation, fully wound/after 24 hours): 1.2 on the wrist, dial up 6.5/ 6.0, dial down 6.2/ 5.2 crown Up 2.5/ 0.7 Crown down 3.1/ 0.9 Crown left 2.1/−0.2 Maximum deviation 4.4/6.2 Average deviation 4.1/ 2.5 Aver Age range: Horizontal position 281°/ 261° Hanging position 262°/250° Dimensions: diameter = 38.87 mm, Height = 12.04 mm, lug width = 22 mm, weight = 180.5 grams Price: 9,100 USD
Score: Strap and buckle (maximum 10 points): exquisite stainless steel bracelet, sturdy and practical folding clasp 9 Case (10): high-quality, well-made case with alternating polished and brushed finishes, sapphire Crystal and screw-in crown. 9 Dial and hands (10): Outstanding marks and hands, unique embossed dial design, perfectly matched hands 8 Design (15): The design follows the famous 44GS with modern modifications; prominent numbers, hands, dial , The iconic appearance. 12 Legibility (5): easy to read during the day, unreadable at night; large date display, perfect hand length 4 Operation (5): screw-in crown is easy to grasp and loosen; screw-in bracelet links, convenient Adjustable, safe folding clasp. 5 Wearing comfort (5): The combination of ergonomic case and bracelet, despite considerable weight, is still comfortable, beautiful bracelet, strong clasp 4 Movement (20): modern with innovative solutions and unique structural features Internal movement, some of which have been patented; long power reserve, modern escapement, high frequency, complex and attractive decorative finishes 18 Scoring results (10): very good, especially on the wrist; in line with Grand Seiko standard. 8 Overall value (10): Compared with other similar watches, the pricing is ambitious, but due to the brand’s attractiveness and iconic status, this is reasonable 8 Total score: 85 points
This article was originally published in the September to October issue of WatchTime 2021. Photos by Grand Seiko, Marcus Kruger and Jennifer Wunder/Pexels.
Tags: Grand Seiko, Japanese watches, limited edition watches, luxury watches, watch testing
The Grand Seiko standard mentioned in the article applies to the caseless watch. According to the Grand Seiko 9SA5 movement webpage, the standard of the Grand Seiko 9SA5 movement assembly table is from -1 s/d to 8 s/d. In addition-have you tested the movement with a Grand Seiko timekeeper? I participated in an event in Grand Seiko, and the representative of Grand Seiko said that traditional timekeepers could not accurately interpret the sound of the dual-pulse 9SA5 movement.
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© 2021 Ebner Publishing International, Inc.
© 2021 Ebner Publishing International, Inc.