This is a manufacture caliber made in-house by Seiko, which achieves high precision with minimal posture error thanks to its high-speed balance, which vibrates 10 times per second and 36,000 times per hour.
The case size is 40mm, making it a convenient size for both business and formal occasions.

The "Mechanical High-Beat GMT" model is equipped with the caliber 9S86, a high-vibration mechanical movement with 36,000 vibrations (10 vibrations per second) and a GMT function.

This is a special edition model produced in a limited run of 500 pieces to commemorate Seiko's 135th anniversary.
This pattern, which represents the countless ridges carved into Mt. Iwate, a famous peak in Iwate Prefecture, as seen from the Shizukuishi High-end Watch Workshop, which consistently produces 9S series mechanical movements, is a special pattern used only on Grand Seiko watches equipped with advanced mechanical movements that are symbolic of Shizukuishi manufacturing.