"While it was not strictly JDM, most were sold in Japan and it was only made for 2-3 years. Inside sits Seiko’s 6139 caliber which is a non hand-winding, single register (minutes) column-wheel integrated chronograph that utilizes parts of the rugged, read: bulletproof, 6106 movement. Day and date are changed quick-set style by pushing in the crown either one or two detents. The watch foregoes hand-winding due to its Magic Lever system that allows for efficient winding no matter which direction the rotor spins. The 6139’s tend to have beefy cases due to their movements but the 6040 actually wears on the smaller side versus other Seiko chronographs of the day." Movements runs well! Chrono Reset nicely. One of the best unblemished bezel you can find on this piece. Most of the others you are aware are faded, not the kind of ghostly faded kind you hope for in vintage Rolex. I paid more than $300 to have it send to the UK watchmaker to have it serviced and overhauled.Selling on a as is basis and head Will Shipped Worldwide, US$650 to include registered shipping. Wise or Bank transfer preferred, Paypal add 5%.