This was the caliber 9SA5. The caliber 9SA5 is a high frequency, in-house Seiko movement (there are no Grand Seikos using outsourced movements – in fact, there are no Seiko watches, period, using outsourced movements) vibrating at 36,000 vph. This is in contrast to the normal beat rate for modern movements, which is generally 28,800 vph. The reason for choosing a higher frequency for an oscillator is that, all things being equal, a watch with a higher frequency will generally exhibit better rate stability, or at least, that is one approach to improving rate stability. A well-known practitioner of alternative solutions is Roger Smith, who is an advocate of the traditional approach, in which a slower beat rate is paired with a larger balance. A fast-beat series-produced movement is, nonetheless, a rarity in modern watchmaking, and the fact that such movements are made by Grand Seiko, and widely used, already places their Hi-Beat watches in a pretty exclusive category of timepieces. But the caliber 9SA5 also had something even less often seen in horology – a new type of escapement.
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