This watch marks a new level of innovation for the Grand Seiko brand as it is the timepiece with the longest power reserve for a 10 beat Hi beat automatic chronograph. It’s named for its TEN beats per second, Three days power reserve, Automatic ChronoGRAPH.
Operating on a newly created 9SC5 movement at ten beats per second, this chronograph was designed to pursue stable accuracy in any condition. The movement – with its 72-hour-long power reserve and 10-beat frequency – as well as the chronograph’s modular mechanism, combining a column wheel for operations and a vertical clutch for transmission, makes this possible. As a result of this watch, the Takumi revised the Grand Seiko testing procedure for mechanical chronographs to create a new inspection standard – from 17 days previously, to twenty days so that the accuracy requirements are also applied to the movement while the chronograph is operating in three different positions.
From the Evolution 9 collection, the pattern on its blue dial resembles a starry winter night on Mount Iwate. The day calendar matches the dial colour for the first time in a Grand Seiko and is positioned between the 4 o’clock and 5 o’clock markers. With a smaller case size than Spring Drive chronograph models, the bezel is black ceramic, whilst the case and bracelet are made from light weight and durable high-intensity titanium.
The watchmakers’ pride in their surroundings is represented from engineering watch movements which emulate the smooth motion of time passing, to creating dials reflecting the beauty of Japanese nature – a Japanese spirituality where each moment is a unique expression unveiled through light and shadow.
Every Grand Seiko features signature high standards of precision, durability and legibility, handcrafted in Japan by Takumi artisans. Grand Seiko: beautifully, precise Japanese watchmaking, from the pinnacle of Seiko Watch Corporation’s in-house manufacture.

The Tentagraph has been nominated for the 2023 GPHG Awards in the Chronograph category.
GPHG, also known as the Grand Prix d’Horlogerie de Genève, recognizes worldwide excellence in watchmaking and is essentially the watch world equivalent of the Oscars.