Tentagraph, the first Grand Seiko mechanical chronograph

Following the positive response from the public at the launch of the Evolution 9 collection during the Geneva Show in 2022, Grand Seiko now reaches a new milestone by expanding its Evolution 9 sports watch range with its first mechanical chronograph, the Tentagraph.

Just like every other Grand Seiko creation, the quest for precision is the spark that fuels the work of master watchmakers and the Tentagraph is a confirmation of this. The calibre powering this extraordinary watch is the 9SC5, based on the revolutionary 9SA5 Hi-Beat calibre already successfully implemented in other models of the brand.

This new calibre beats at a frequency of ten alternations per second, guaranteeing high precision in measuring the time and elapsed time. Moreover, thanks to its energy-saving escapement and two barrels, the watch has a three-day power reserve even when the chronograph is running, making Tentagraph the 10-beat chronograph with the longest power reserve in the industry*. In addition, the Tentagraph undergoes a new, extended test procedure to test its accuracy.

For all Grand Seiko mechanical movements, the precision of the movement is tested in six positions and at three temperatures over a period of 17 days. For the Tentagraph, on the other hand, another three days of testing are added to this process, during which the precision is analysed in three positions while the chronograph is running.

The new movement features the revolutionary double impulse escapement, which efficiently transmits energy to the free-sprung balance both indirectly via the pallet fork and directly from the escape wheel. MEMS technology guarantees extremely precise, light and durable escapement components and endows the escapement with greater energy efficiency for a long power reserve.

Characteristic features of a fine modern chronograph, a vertical clutch and a column wheel together guarantee high precision and functionality. The vertical clutch eliminates any vibration or jerking of the hands when the chronograph is running and improves the accuracy of the measurement, while the column wheel ensures precise control of the chronograph. The movement features a three-pronged hammer, which ensures that when the reset button is pressed, the hands immediately return to zero, in perfect synchronisation.

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