Grand Seiko Cal. 9S86 is a high-beat automatic movement with date and independently-adjustable central GMT hand. It is closely related to Cal. 9S85, which lacks the GMT hand. It was introduced in 2014 at Baselworld and remains in production as of 2020.
Cal. 9S86 features a proprietary Spron 610 alloy for the mainspring, with improved impact and magnetic resistance. The escapement is created using MEMS technology for precision. The mainspring is constructed of the Spron 530 alloy for higher torque and increased power reserve.
Cal. 9S86 is used in the Grand Seiko SBGJ series of watches.
A “Special” tune of the 9S86 was used in a few models, notably the 2018 SBGJ229. This achieves accuracy of -2/+4 seconds.